http://nanowiki.no/api.php?action=feedcontributions&feedformat=atom&user=Fredrimu 2026-04-06T00:59:53Z Brukerbidrag MediaWiki 1.44.2 http://nanowiki.no/index.php?title=Hovedekskursjon_2010&diff=4155 2009-08-27T12:52:49Z

<p>Fredrimu: /* Nanoteknologi-bedrifter */</p> <hr /> <div>Denne artikkelen inneholder informasjon om hovedekskursjonen til MTNANOs kull 2007. Det er bestemt at reiemålet blir Kinas hovedstad Beijing og omegn.<br /> <br /> <br /> <br /> = Tidsplan =<br /> * 24.03.2009: Deadline for [http://www.timini.no/forum/viewtopic.php?t=1622 idémyldring på forumet]<br /> * 04.05.2009 10:15-12:00, R3: Allmøte med presentasjon av reisemålene og avstemming<br /> * 19.03.2010: Planlagt avreise<br /> * 09.04.2010: Planlagt hjemreise<br /> <br /> =Om Kina som reisemål=<br /> <br /> ===Drillo-fakta===<br /> <br /> ===Nanoteknologi-bedrifter===<br /> <br /> <br /> '''Advapowder'''<br /> Produces nanoscale diamond powder. <br /> <br /> '''AgroMicron (HongKong)'''<br /> The company develops Rapid Early Detection products. These products identify possible pathological threats from bioterrorism to pathogens plaguing global agriculture, animals and people. Test arrays include nanoscale molecule detection techniques.<br /> <br /> '''AlphaNano Technology (Australia(?))'''<br /> A manufacturer of carbon nanotubes and other nanoparticles.<br /> <br /> '''Anson Nanotechnology Group (Hong Kong)'''<br /> Manufactures nanoparticulate antibacterial dressings.<br /> <br /> '''Arry International Group Limited (Hong Kong)'''<br /> Supplier of a wide variety of nano materials, including carbon nanotubes (CNTs) and nano elements as as well as nano oxides (rare earth, metal, and non-metal).<br /> <br /> '''Beijing Chamgo Nano-Tech'''<br /> Manufactures antimicrobial fibers and plastics and nanocomposite materials.<br /> <br /> '''Beijing HuiHaihong Nano-ST'''<br /> The company is mainly engaged in the application research of nanometer-structured material, R&amp;D of new products, technology transfer, technical consultation, technical service, production and management of the newly developed products.<br /> <br /> '''Chengdu Alpha Nano Technology'''<br /> A supplier of carbon nanotubes and various nanopowders.<br /> <br /> '''Chengdu Organic Chemistry Co.'''<br /> Producer of carbon nanotubes.<br /> <br /> '''Chengyin Technology'''<br /> Producer of nanoparticles.<br /> <br /> '''China Rare Metal Material'''<br /> CRM offers a wide range of nanoparticulate specialist metals, oxides, alloys and inorganic chemical compounds.<br /> <br /> '''Chongyi Zhangyuan Tungsten Co., Ltd.'''<br /> Producer of tungsten and tungsten carbide nanopowders.<br /> <br /> '''EnvironmentalCare (Hong Kong)'''<br /> Manufactures nano-TiO2 catalytic surface coating materials.<br /> <br /> '''FCC'''<br /> The company produces 6 series of more than 20 different items bentonite refined products,including NANOLIN series of nanoclay.<br /> <br /> '''Futuresoft Technologies (Beijing)'''<br /> Futuresoft Technologies Inc. is specialized in technologies in plastic materials, their processing equipment and processed products. FTI offers turn-key production systems of wood-plastic composite, extruders, and dies, especially profile dies for wood-plastic, PVC, and TPE. Their polymer nanocomposite technology has been able to make the composite to have much higher property enhancement than those by other technology.<br /> <br /> '''HeFei Kaier Nanometer Technology Development Co.'''<br /> Specializes in nitride and carbide series of nanoparticle ceramic powders.<br /> <br /> '''HeJi, Inc.'''<br /> Producer of carbon nanotubes.<br /> <br /> '''Huizhou TianYi Rare Material'''<br /> Manufacturer of nanopowders.<br /> <br /> '''Jiangsu Changtai Nanometer Material Co, Ltd.'''<br /> Producer of nanoparticles.<br /> <br /> '''Jinri Diamond'''<br /> The company produces diamond abrasives. Among its products are nanodiamond materials.<br /> <br /> '''NaBond'''<br /> Focused on development, manufacture and application of nanomaterials and adhesives.<br /> <br /> '''Nano-Group Holdings (Hong Kong)'''<br /> Provides nanotechnology applications for the textile and garment industries.<br /> <br /> '''Semiconductor Manufacturing International Corporation (SMIC) (Shanghai)'''<br /> SMIC is one of the leading semiconductor foundries in the world and the largest and most advanced foundry in Mainland China, providing integrated circuit manufacturing service at 0.35 micron to 65 nanometer and finer line technologies.<br /> <br /> '''Shanghai ADD Nano-ST'''<br /> Manufactures PTFE nanopowders for printing, dyeing, and cosmetic applications.<br /> <br /> '''ShangHai Allrun Nano Science &amp; Technology'''<br /> Allrun Nano's technologies consist of distinct nanomaterial manufacturing processes, surface treatment technologies of nanomaterial, and its bio-medical application technologies. Allrun Nano has created an integrated platform of nanomaterial technologies that are designed to deliver nanomaterial solutions for market applications.<br /> <br /> '''Shanghai Huzheng Nano Technology'''<br /> Producer of wide range of nanoparticles, coating supplements and finishing agents.<br /> <br /> '''Shanghai Shanghui Nano Science and Technology'''<br /> The company specializes in the R&amp;D, production and distribution of high-tech industrial products of nanomaterials. In possession of its own centre of R&amp;D and integrating production with industrialization, the company cooperates with colleges and scientific institutions with regard to the projects of nanomaterials and technologies.<br /> <br /> '''Shenzen Nano-Technologies Port Co., Ltd.'''<br /> Producer of carbon nanotubes.<br /> <br /> '''Shenzhen JinGangYuan New Material Development'''<br /> The company specializes in developing and manufacturing nanodiamond and other related products.<br /> <br /> '''Shenzhen Junye Nano Material Co.'''<br /> Produces metal nanoparticles.<br /> <br /> '''Shenzhen Nanotechnologies'''<br /> The company is focusing on the R&amp;D, manufacture and application of carbon nanotubes.<br /> <br /> '''Sokang Nano (Beijing)'''<br /> Develops several lines of nanotech product including nano coating, nano coating additive, nano air cleaner module and nano water cleaning module.<br /> <br /> '''Sumi Long Nanotechnology Materials (Shenzen)'''<br /> (Site in Chinese) A subsidiary of Sumitomo Osaka Cement, the company develops and manufactures antimagnetic, anti-reflection coatings with nanoparticles.<br /> <br /> '''Sun Nanotech Co, Ltd. (Nanchang)'''<br /> Supplier of carbon nanotubes.<br /> <br /> '''Texnology Nano Textile (HONG KONG)'''<br /> Applies nanocoatings to textile fibers and materials.<br /> <br /> '''TiPE (fant ikke side)'''<br /> TiPE is a leading nano photocatalyst manufacturer in China, with its proprietary advanced Nano-hydrosynthetic™ technology. TiPE also is the biggest hydrosynthetic photocatalyst manufacturer in China.<br /> <br /> '''TitanPE Technology (Shanghai) Inc.'''<br /> Produces nano photocatalysts.<br /> <br /> '''Yantai Jialong Nano Industry (Yantai)'''<br /> The company conducts research and development of nanomaterials. It is the 863 Program Industrialization Base, Shandong Nanocoating Engineering &amp; technology Research Center and Yantai Nano Engineering &amp; Technology Research Center.<br /> <br /> '''Zhejiang Fenghong Clay Chemicals'''<br /> Engages in research, development, manufacture and trade of refined clay related products such as organoclay rheological additives ornanoclay for polymers.<br /> <br /> '''Zibo ShineSo Chemical New Material'''<br /> ShineSo specializes in the R&amp;D, manufacturing distribution and technical service of advanced ceramic materials including nanopowders.<br /> <br /> ===Økonomi===<br /> <br /> I følge pintprice.com er det store geografiske variasjoner i ølprisene i Kina; fra under 2 kr i Changchun til over 40 kr i Shanghai. I Beijing er prisen ca 10 kr. <br /> <br /> ===Attraksjoner=== <br /> <br /> ===Universiteter med samarbeidsavtaler med NTNU===<br /> <br /> ===Forslag til steder å dra 3.uke===<br /> * Sanya<br /> <br /> Average Data Apr <br /> <br /> Average High (C) 29/31<br /> <br /> Average Low (C) 23/25<br /> <br /> Rain (mm) 30/35<br /> <br /> <br /> [[Bilde:Sanya.jpg]]<br /> <br /> ===Annet===<br /> I Kina selges det ikke tamponger av noe slag. Kilde: Frisør Tango Ulefoss<br /> <br /> =Forslag til reisemål som ble forkastet=<br /> <br /> ==California==<br /> <br /> ===Drillo-fakta===<br /> Hovedstad: Sacramento<br /> <br /> Guvernør: Arnold Schwarzenegger (R)<br /> <br /> ===Nanoteknologi-bedrifter=== <br /> <br /> Silicon Valley ligger den sørlige derlen av San Fransico Bay Area i Northern California og har fått navnet sitt på grunn av områdets høye konsentrasjon av innovative elektronikkbedrifter. Med tiden har dette området blitt et slags symbol på nyskapning, entrepenørskap og ingeniørbragder. Silicon Valley er USAs ledende high-tech industriområde med bedrifter som (med forbehold om at ikke alle er direkte nanorelevante):<br /> *'''Advanced Micro Devices (AMD)'''<br /> *Apple Inc.<br /> *'''Applied Materials'''<br /> *Google<br /> *[http://www.intel.com/ '''Intel''']<br /> *LSI Logic<br /> *'''National Semiconductor'''<br /> *Sun Microsystems<br /> *Asus<br /> *Atari<br /> *Cypress Semiconductor<br /> *Facebook<br /> *'''IBM Almaden Research Center'''<br /> *Opera Software<br /> *Tesla Motors<br /> *'''Sun Power'''<br /> *NASA Ames Research Center<br /> *Quantum Dot Corporation<br /> <br /> ===Økonomi===<br /> *Visum<br /> **Må ha elektronsik pass, for nytt pass 450 NOK (Kilde: politi.no)<br /> **Koster 750 NOK (Kilde: Den amerikanske ambassade)<br /> *Reiseforsikring<br /> **Kan gjøres billig, eller f.eks. Europeiske, verden helår: 1215 NOK<br /> *Flybilletter<br /> **Trondheim - San Francisco apprxo. 7 000 - 8 000 NOK (Kilde: kelkoo.no)<br /> **Oslo - San Francisco ned mot 5 000 NOK (Kilde: kelkoo.no)<br /> *Overnatting<br /> **approx. 200 NOK night^-1 for hostel (Kilde: hostels.com)<br /> *Øl<br /> **25-35 NOK arbitary beer unit^-1. I byen Chico kan man imidlertid få en duggfrisk til under 12 kr (Kilde: pintprice.com).<br /> <br /> ===Attraksjoner===<br /> <br /> *San Fransisco<br /> **Alcatraz<br /> **Golden Gate<br /> **Golden Gate Park<br /> **Myth Busters + lignende serier fra Discovery Channel?<br /> **Twin peaks<br /> *Los Angeles<br /> **Santa Monica Beach<br /> **Venice Beach<br /> **Hollywood<br /> **Long Beach<br /> **Beverly Hills<br /> *San Diego<br /> ** Varme, digge sandstrender<br /> *Tijuana, Mexico<br /> **Beryktet natteliv<br /> *Central Valley<br /> **Sierra Nevada Mountains, 800 miles med turmuligheter<br /> **Kul ørken<br /> *Santa Barbara<br /> ** vakre strender og surfere<br /> <br /> ===Universiteter===<br /> *California Institute of Technology (CALTECH)<br /> **Kavli nanoscience institute driver forskning blant annet innen bionanoteknologi og nanofotinikk<br /> *University of California @ Berkeley, San Diego og Santa Barbara<br /> **Har utvekslingsavtale med NTNU<br /> <br /> ===Annet===<br /> *Infrastruktur<br /> ** lav språkbarriere<br /> ** Relativt bra og billig togtransport innenfor staten, for eksempel har Bay Area Rapid Transit typsisk 15 min ruter mellom San Francisco Peninsula og Oakland, Berkeley, Fremont, Walnut Creek og andre byer i East Bay.<br /> <br /> ==Vest-Europa==<br /> <br /> ===Drillo-fakta===<br /> <br /> ===Nanoteknologi-bedrifter=== <br /> <br /> ===Økonomi===<br /> <br /> Vanlige ølpriser er Frankrike er ca 50 kr i følge pintprice.com. 40 kr er typisk i Barcelona, mens man i Sveits slipper unna med 35 kr.<br /> [[Image:Inter.jpg|left|thumb|500px|]]<br /> <br /> ===Attraksjoner===<br /> *Frankrike<br /> ** Paris!<br /> ** Vinsmaking i Bourgogne, Champagne eller Bordeaux<br /> <br /> ===Universiteter med samarbeidsavtaler med NTNU===<br /> *Frankrike<br /> ** INSA Toulouse<br /> ** UTT<br /> **Université de téchnologie de Compiègne <br /> **INPG - ENSIMAG<br /> **Ecole Superieure d'Ingenieurs de Marseille <br /> **Ecole National Chimie de Paris <br /> **Université de Poitiers <br /> **Institut National Polytechnique de Grenoble<br /> <br /> Bare i Paris er det 7 universiteter, 6 &quot;grandes écoles&quot; og 84 instutisjoner som kommer under den nasjonale handlingsplanen for nanoteknologi i Frankrike.<br /> <br /> ===Annet===<br /> <br /> <br /> ==Japan==<br /> <br /> ===Drillo-fakta===<br /> Hovedstad: Tokyo<br /> <br /> Innbygggertall: 127 millioner<br /> <br /> Språk: Japansk<br /> <br /> ===Nanoteknologi-bedrifter=== <br /> <br /> ===Økonomi===<br /> <br /> Pintprice.com hevder at snittprisen på en øl i Japan er 35 kr. I hovedstaden Tokyo er prisen opp mot 50-lappen. <br /> <br /> ===Attraksjoner===<br /> Byen Nagano (De japanske Alper)<br /> De fleste kjenner Nagano som vertsby for vinter-OL 1998. Byen er den største i området og blant dens fineste severdighet er Zenkoji tempelet som absolutt bør ses hvis man kommer til de japanske alpene.<br /> <br /> Skiområdet (De japanske Alper)<br /> De berømte skisportsstedene ligger et stykke utenfor Nagano. Mange av de beste skiområdene ligger i Shiga platået og i nasjonalparken Joshin-Etsu Kogen Kokuritsu -Koen. Innimellom alle disse skisportsstedene ligger mange deilige kursteder.<br /> <br /> De fem sjøene ved Fuji (Fujiyama)<br /> I nærheten av Fuji ligger De fem sjøene. Sjøene er berømte for deres skjønnhet og det er mulig å dyrke vannsport ved sjøene. Det er også forlystelsesparker i området. Man kommer lettest ut til sjøene med buss eller svevebane.<br /> <br /> Kursteder ved Hakone (Fujiyama)<br /> Hvis man er til kursteder og varme kilder bør man reise til Hakone. De fleste kurstedene ligger omkring Ashinoko sjøen. Prøv en seiltur på sjøen eller ta svevebanen eller toget til Owakudani hvor de fleste varme kildene ligger.<br /> <br /> Atombombekuppelen (Genbaku Domu) (Hiroshima)<br /> Genbaku Domu er det siste som står tilbake av vitnesbyrd på atombombens ødeleggelser i 1945. Opprinnelig var bygningen en industrihall, men stålskjelettet som står tilbake minner om en langt vakrere bygning. Bygningens minner om blodig fortid står i skarp kontrast til nåtidens Hiroshima.<br /> <br /> Hiroshima borgen (Hiroshima)<br /> Hiroshima borgen er, som alt annet i Hiroshima, ikke mer enn 55 år gammel. Allikevel lever borgen opp til alle ens fantasier om gammel japansk middelalderborg. I tårnet er det en spennende utstilling med våpen og rustninger.<br /> <br /> Torii porten (Hiroshima)<br /> Torii porten ligger 20 kilometer fra Hiroshima. De fleste vil gjenkjenne den fra bilder og film om Japan uten å kjenne den ved navn. Torii porten er 17 meter høy, bygget av rødt tre og står midt ute i vannet utenfor Shintotempel øyen Miyajima. Nyt også den praktfulle naturen på øyen.<br /> <br /> Fjellet Fuji (Japan)<br /> Fuji er Japans høyeste fjell. Offisielt kan man kun bestige Fuji i juli og august, men det kan i virkeligheten gjøres hele året, selv om det krever en del rutine i vinterhalvåret. Skiltingen er god og man går seg ikke bort.<br /> <br /> Meiji Jingu Tempelet (Tokyo)<br /> Tempelet er imponerende og ligger i en av Tokyos vakre parker og er blant de helligste i Japan. Nyttårsdag besøker mange japanere dette tempelet iført kimonoer. Tempelet er dedikert til keiser Meiji som i sin tid åpnet Japan for omverdenen. Tempelet inneholder mange av keiserens personlige eiendeler. Parkens irishage er blant Japans vakreste.<br /> <br /> Sanjusangendo Tempelet (Kyoto)<br /> Sanjusangendo tempelet i Kyoto er et imponerende stort tempel. Det stod ferdig i 1266 og de 1001 statuene er et av Kamukara periodens mesterverker. Den 15. januar holdes den årlige bueskytingskonkurransen. En tradisjon som stammer fra det 16. århundre.<br /> <br /> Gullpaviljongen (Kyoto)<br /> Kinkakuji (gullpaviljongen) er en av Kyotos absolutte severdigheter. Tempelet ble oppført i det 14. århundre, men måtte gjenoppføres i 1955 etter at en sinnsyk tempelprest brendte det ned. Tempelet er dekket med bladgull og er en nøyaktig kopi av det gamle Kinkakuji.<br /> <br /> Keiserpalasset i Kyoto (Kyoto)<br /> Keiserpalasset er en av de få serverdigheten i Kyotos sentrum. Det nåværende palasset ble oppført i 1855 som erstatning for et tidligere nedbrendt palass. Palasset kan kun besøkes i grupper. Rundvisningene er veldig ettertraktet og det kan anbefales å søke om plass til disse turene allerede en dag i forveien.<br /> <br /> Byen Nara (Nara)<br /> Byen Nara ligger en halv times togtur fra Kyoto. I Nara gjenfinner man Kyotos særlige atmosfære. Byen ble i 710 Japans første permanente hovedstad og har mange velbevarte templer. I Nara Park går det tamme hjort rundt mellom templene.<br /> <br /> Borgen i Himeji (Osaka)<br /> Himeji ligger halvannen times togtur fra Osaka. Byen rommer kanskje Japans vakreste borg som mange nok vil huske fra tv-serien &quot;Shogun&quot;. Den Hvite Hejres Borg (Shirasagi-jo) er et fantastisk byggeri som med sine hvite murer og kurvede tegltak emmer av østens mystikk, innvendig som utvendig. Til borgen er det knyttet to museer og den berømte kirkegården Nagayama.<br /> <br /> Borgen i Osaka (Osaka)<br /> Borgen i Osaka byr på våpen og maleriutstillinger. Borgen er opprinnelig fra det 16. århundre, men har brendt ned et par ganger siden. Borgen er restaurert og har innvendig heis. Ved siden av borgen ligger Osaka bymuseum med samlinger relatert til byens historie samt en mindre keramikksamling.<br /> <br /> Senri Expo Park (Osaka)<br /> Litt nord for Osaka ligger Senri Expo Park hvor Expo ble holdt i 1970. Her finner man blant annet den vakre landskapshagen som ble anlagt i forbindelse med Expo utstillingen. Det hører også et etnologisk museum til parken hvor det utstilles ting og film fra hele verden.<br /> <br /> Bryggeriet i Sapporo (Sapporo)<br /> På Sapporos bryggeri kan alle ølelskere komme på en gratis rundvisning og smake den gode japanske bryggekunst.<br /> <br /> Nakajima Koen parken (Sapporo)<br /> Ønsker man en forsmak på Hokkaidos skjønne natur bør man besøke Nakajima Koen parken. Her kan man slappe av i parkens landskapshage og besøke det historiske tehuset.<br /> <br /> Disneyland i Tokyo (Tokyo)<br /> Disneyland i Tokyo er en tro kopi av Disneyland i California og har de samme attraksjonene. Forlystelsesparken ble innviet i 1983 og har vært en enorm suksess siden. Hvis man ennå ikke har opplevd Disneyland bør man gripe sjansen her. For å unngå trengsel bør man dra der i hverdagene.<br /> <br /> Ginza distriktet (Tokyo)<br /> Litt sydøst for keiserpalasset ligger Ginza distriktet hvor den mest kjøpelystne kan slå seg løs. Her ligger det mange spesialbutikker og stormagasiner. I kvarteret kan man finne mange utenlandske aviser og tollfrie butikker.<br /> <br /> Keiserpalasset (Tokyo)<br /> Keiserpalasset er en av de severdighetene man bør besøke under oppholdet i Tokyo. Det er ikke adgang til selve palasset hvor keiserfamilien bor, men gå en tur i parken og nyt utsikten innover palasset.<br /> <br /> ===Universiteter med samarbeidsavtaler med NTNU===<br /> <br /> ===Annet===<br /> <br /> ==Singapore og Malaysia==<br /> <br /> ===Drillo-fakta===<br /> <br /> ===Nanoteknologi-bedrifter=== <br /> <br /> ===Økonomi===<br /> <br /> En øl kan fås til 20 kr i Singapore i følge pintprice.com, men man må regne med minst det dobbelte mange steder. Snittprisen i Malaysia er 37 kr. <br /> <br /> ===Attraksjoner=== <br /> <br /> ===Universiteter med samarbeidsavtaler med NTNU===<br /> <br /> ===Annet===</div>

Fredrimu http://nanowiki.no/index.php?title=Hovedekskursjon_2010&diff=4154 2009-08-27T12:43:17Z

<p>Fredrimu: /* Nanoteknologi-bedrifter */</p> <hr /> <div>Denne artikkelen inneholder informasjon om hovedekskursjonen til MTNANOs kull 2007. Det er bestemt at reiemålet blir Kinas hovedstad Beijing og omegn.<br /> <br /> <br /> <br /> = Tidsplan =<br /> * 24.03.2009: Deadline for [http://www.timini.no/forum/viewtopic.php?t=1622 idémyldring på forumet]<br /> * 04.05.2009 10:15-12:00, R3: Allmøte med presentasjon av reisemålene og avstemming<br /> * 19.03.2010: Planlagt avreise<br /> * 09.04.2010: Planlagt hjemreise<br /> <br /> =Om Kina som reisemål=<br /> <br /> ===Drillo-fakta===<br /> <br /> ===Nanoteknologi-bedrifter===<br /> <br /> <br /> '''Advapowder'''<br /> Produces nanoscale diamond powder. <br /> <br /> '''AgroMicron (HongKong)'''<br /> The company develops Rapid Early Detection products. These products identify possible pathological threats from bioterrorism to pathogens plaguing global agriculture, animals and people. Test arrays include nanoscale molecule detection techniques.<br /> <br /> '''AlphaNano Technology (Australia(?))'''<br /> A manufacturer of carbon nanotubes and other nanoparticles.<br /> <br /> '''Anson Nanotechnology Group (Hong Kong)'''<br /> Manufactures nanoparticulate antibacterial dressings.<br /> <br /> '''Arry International Group Limited (Hong Kong)'''<br /> Supplier of a wide variety of nano materials, including carbon nanotubes (CNTs) and nano elements as as well as nano oxides (rare earth, metal, and non-metal).<br /> <br /> '''Beijing Chamgo Nano-Tech'''<br /> Manufactures antimicrobial fibers and plastics and nanocomposite materials.<br /> <br /> '''Beijing HuiHaihong Nano-ST'''<br /> The company is mainly engaged in the application research of nanometer-structured material, R&amp;D of new products, technology transfer, technical consultation, technical service, production and management of the newly developed products.<br /> <br /> '''Chengdu Alpha Nano Technology'''<br /> A supplier of carbon nanotubes and various nanopowders.<br /> <br /> '''Chengdu Organic Chemistry Co.'''<br /> Producer of carbon nanotubes.<br /> <br /> '''Chengyin Technology'''<br /> Producer of nanoparticles.<br /> <br /> '''China Rare Metal Material'''<br /> CRM offers a wide range of nanoparticulate specialist metals, oxides, alloys and inorganic chemical compounds.<br /> <br /> '''Chongyi Zhangyuan Tungsten Co., Ltd.'''<br /> Producer of tungsten and tungsten carbide nanopowders.<br /> <br /> '''EnvironmentalCare (Hong Kong)'''<br /> Manufactures nano-TiO2 catalytic surface coating materials.<br /> <br /> '''FCC'''<br /> The company produces 6 series of more than 20 different items bentonite refined products,including NANOLIN series of nanoclay.<br /> <br /> '''Futuresoft Technologies (Beijing)'''<br /> Futuresoft Technologies Inc. is specialized in technologies in plastic materials, their processing equipment and processed products. FTI offers turn-key production systems of wood-plastic composite, extruders, and dies, especially profile dies for wood-plastic, PVC, and TPE. Their polymer nanocomposite technology has been able to make the composite to have much higher property enhancement than those by other technology.<br /> <br /> '''HeFei Kaier Nanometer Technology Development Co.'''<br /> Specializes in nitride and carbide series of nanoparticle ceramic powders.<br /> <br /> '''HeJi, Inc.'''<br /> Producer of carbon nanotubes.<br /> <br /> '''Huizhou TianYi Rare Material'''<br /> Manufacturer of nanopowders.<br /> <br /> '''Jiangsu Changtai Nanometer Material Co, Ltd.'''<br /> Producer of nanoparticles.<br /> <br /> '''Jinri Diamond'''<br /> The company produces diamond abrasives. Among its products are nanodiamond materials.<br /> <br /> '''NaBond'''<br /> Focused on development, manufacture and application of nanomaterials and adhesives.<br /> <br /> '''Nano-Group Holdings (Hong Kong)'''<br /> Provides nanotechnology applications for the textile and garment industries.<br /> <br /> '''Semiconductor Manufacturing International Corporation (SMIC) (Shanghai)'''<br /> SMIC is one of the leading semiconductor foundries in the world and the largest and most advanced foundry in Mainland China, providing integrated circuit manufacturing service at 0.35 micron to 65 nanometer and finer line technologies.<br /> <br /> '''Shanghai ADD Nano-ST'''<br /> Manufactures PTFE nanopowders for printing, dyeing, and cosmetic applications.<br /> <br /> '''ShangHai Allrun Nano Science &amp; Technology'''<br /> Allrun Nano's technologies consist of distinct nanomaterial manufacturing processes, surface treatment technologies of nanomaterial, and its bio-medical application technologies. Allrun Nano has created an integrated platform of nanomaterial technologies that are designed to deliver nanomaterial solutions for market applications.<br /> <br /> '''Shanghai Huzheng Nano Technology'''<br /> Producer of wide range of nanoparticles, coating supplements and finishing agents.<br /> <br /> '''Shanghai Shanghui Nano Science and Technology'''<br /> The company specializes in the R&amp;D, production and distribution of high-tech industrial products of nanomaterials. In possession of its own centre of R&amp;D and integrating production with industrialization, the company cooperates with colleges and scientific institutions with regard to the projects of nanomaterials and technologies.<br /> <br /> '''Shenzen Nano-Technologies Port Co., Ltd.'''<br /> Producer of carbon nanotubes.<br /> <br /> '''Shenzhen JinGangYuan New Material Development'''<br /> The company specializes in developing and manufacturing nanodiamond and other related products.<br /> <br /> '''Shenzhen Junye Nano Material Co.'''<br /> Produces metal nanoparticles.<br /> <br /> '''Shenzhen Nanotechnologies'''<br /> The company is focusing on the R&amp;D, manufacture and application of carbon nanotubes.<br /> <br /> '''Sokang Nano (Beijing)'''<br /> Develops several lines of nanotech product including nano coating, nano coating additive, nano air cleaner module and nano water cleaning module.<br /> <br /> '''Sumi Long Nanotechnology Materials (Shenzen)'''<br /> (Site in Chinese) A subsidiary of Sumitomo Osaka Cement, the company develops and manufactures antimagnetic, anti-reflection coatings with nanoparticles.<br /> <br /> '''Sun Nanotech Co, Ltd.'''<br /> Supplier of carbon nanotubes.<br /> <br /> '''Texnology Nano Textile'''<br /> Applies nanocoatings to textile fibers and materials.<br /> <br /> '''TiPE'''<br /> TiPE is a leading nano photocatalyst manufacturer in China, with its proprietary advanced Nano-hydrosynthetic™ technology. TiPE also is the biggest hydrosynthetic photocatalyst manufacturer in China.<br /> <br /> '''TitanPE Technology (Shanghai) Inc.'''<br /> Produces nano photocatalysts.<br /> <br /> '''Yantai Jialong Nano Industry'''<br /> The company conducts research and development of nanomaterials. It is the 863 Program Industrialization Base, Shandong Nanocoating Engineering &amp; technology Research Center and Yantai Nano Engineering &amp; Technology Research Center.<br /> <br /> '''Zhejiang Fenghong Clay Chemicals'''<br /> Engages in research, development, manufacture and trade of refined clay related products such as organoclay rheological additives ornanoclay for polymers.<br /> <br /> '''Zibo ShineSo Chemical New Material'''<br /> ShineSo specializes in the R&amp;D, manufacturing distribution and technical service of advanced ceramic materials including nanopowders.<br /> <br /> ===Økonomi===<br /> <br /> I følge pintprice.com er det store geografiske variasjoner i ølprisene i Kina; fra under 2 kr i Changchun til over 40 kr i Shanghai. I Beijing er prisen ca 10 kr. <br /> <br /> ===Attraksjoner=== <br /> <br /> ===Universiteter med samarbeidsavtaler med NTNU===<br /> <br /> ===Forslag til steder å dra 3.uke===<br /> * Sanya<br /> <br /> Average Data Apr <br /> <br /> Average High (C) 29/31<br /> <br /> Average Low (C) 23/25<br /> <br /> Rain (mm) 30/35<br /> <br /> <br /> [[Bilde:Sanya.jpg]]<br /> <br /> ===Annet===<br /> I Kina selges det ikke tamponger av noe slag. Kilde: Frisør Tango Ulefoss<br /> <br /> =Forslag til reisemål som ble forkastet=<br /> <br /> ==California==<br /> <br /> ===Drillo-fakta===<br /> Hovedstad: Sacramento<br /> <br /> Guvernør: Arnold Schwarzenegger (R)<br /> <br /> ===Nanoteknologi-bedrifter=== <br /> <br /> Silicon Valley ligger den sørlige derlen av San Fransico Bay Area i Northern California og har fått navnet sitt på grunn av områdets høye konsentrasjon av innovative elektronikkbedrifter. Med tiden har dette området blitt et slags symbol på nyskapning, entrepenørskap og ingeniørbragder. Silicon Valley er USAs ledende high-tech industriområde med bedrifter som (med forbehold om at ikke alle er direkte nanorelevante):<br /> *'''Advanced Micro Devices (AMD)'''<br /> *Apple Inc.<br /> *'''Applied Materials'''<br /> *Google<br /> *[http://www.intel.com/ '''Intel''']<br /> *LSI Logic<br /> *'''National Semiconductor'''<br /> *Sun Microsystems<br /> *Asus<br /> *Atari<br /> *Cypress Semiconductor<br /> *Facebook<br /> *'''IBM Almaden Research Center'''<br /> *Opera Software<br /> *Tesla Motors<br /> *'''Sun Power'''<br /> *NASA Ames Research Center<br /> *Quantum Dot Corporation<br /> <br /> ===Økonomi===<br /> *Visum<br /> **Må ha elektronsik pass, for nytt pass 450 NOK (Kilde: politi.no)<br /> **Koster 750 NOK (Kilde: Den amerikanske ambassade)<br /> *Reiseforsikring<br /> **Kan gjøres billig, eller f.eks. Europeiske, verden helår: 1215 NOK<br /> *Flybilletter<br /> **Trondheim - San Francisco apprxo. 7 000 - 8 000 NOK (Kilde: kelkoo.no)<br /> **Oslo - San Francisco ned mot 5 000 NOK (Kilde: kelkoo.no)<br /> *Overnatting<br /> **approx. 200 NOK night^-1 for hostel (Kilde: hostels.com)<br /> *Øl<br /> **25-35 NOK arbitary beer unit^-1. I byen Chico kan man imidlertid få en duggfrisk til under 12 kr (Kilde: pintprice.com).<br /> <br /> ===Attraksjoner===<br /> <br /> *San Fransisco<br /> **Alcatraz<br /> **Golden Gate<br /> **Golden Gate Park<br /> **Myth Busters + lignende serier fra Discovery Channel?<br /> **Twin peaks<br /> *Los Angeles<br /> **Santa Monica Beach<br /> **Venice Beach<br /> **Hollywood<br /> **Long Beach<br /> **Beverly Hills<br /> *San Diego<br /> ** Varme, digge sandstrender<br /> *Tijuana, Mexico<br /> **Beryktet natteliv<br /> *Central Valley<br /> **Sierra Nevada Mountains, 800 miles med turmuligheter<br /> **Kul ørken<br /> *Santa Barbara<br /> ** vakre strender og surfere<br /> <br /> ===Universiteter===<br /> *California Institute of Technology (CALTECH)<br /> **Kavli nanoscience institute driver forskning blant annet innen bionanoteknologi og nanofotinikk<br /> *University of California @ Berkeley, San Diego og Santa Barbara<br /> **Har utvekslingsavtale med NTNU<br /> <br /> ===Annet===<br /> *Infrastruktur<br /> ** lav språkbarriere<br /> ** Relativt bra og billig togtransport innenfor staten, for eksempel har Bay Area Rapid Transit typsisk 15 min ruter mellom San Francisco Peninsula og Oakland, Berkeley, Fremont, Walnut Creek og andre byer i East Bay.<br /> <br /> ==Vest-Europa==<br /> <br /> ===Drillo-fakta===<br /> <br /> ===Nanoteknologi-bedrifter=== <br /> <br /> ===Økonomi===<br /> <br /> Vanlige ølpriser er Frankrike er ca 50 kr i følge pintprice.com. 40 kr er typisk i Barcelona, mens man i Sveits slipper unna med 35 kr.<br /> [[Image:Inter.jpg|left|thumb|500px|]]<br /> <br /> ===Attraksjoner===<br /> *Frankrike<br /> ** Paris!<br /> ** Vinsmaking i Bourgogne, Champagne eller Bordeaux<br /> <br /> ===Universiteter med samarbeidsavtaler med NTNU===<br /> *Frankrike<br /> ** INSA Toulouse<br /> ** UTT<br /> **Université de téchnologie de Compiègne <br /> **INPG - ENSIMAG<br /> **Ecole Superieure d'Ingenieurs de Marseille <br /> **Ecole National Chimie de Paris <br /> **Université de Poitiers <br /> **Institut National Polytechnique de Grenoble<br /> <br /> Bare i Paris er det 7 universiteter, 6 &quot;grandes écoles&quot; og 84 instutisjoner som kommer under den nasjonale handlingsplanen for nanoteknologi i Frankrike.<br /> <br /> ===Annet===<br /> <br /> <br /> ==Japan==<br /> <br /> ===Drillo-fakta===<br /> Hovedstad: Tokyo<br /> <br /> Innbygggertall: 127 millioner<br /> <br /> Språk: Japansk<br /> <br /> ===Nanoteknologi-bedrifter=== <br /> <br /> ===Økonomi===<br /> <br /> Pintprice.com hevder at snittprisen på en øl i Japan er 35 kr. I hovedstaden Tokyo er prisen opp mot 50-lappen. <br /> <br /> ===Attraksjoner===<br /> Byen Nagano (De japanske Alper)<br /> De fleste kjenner Nagano som vertsby for vinter-OL 1998. Byen er den største i området og blant dens fineste severdighet er Zenkoji tempelet som absolutt bør ses hvis man kommer til de japanske alpene.<br /> <br /> Skiområdet (De japanske Alper)<br /> De berømte skisportsstedene ligger et stykke utenfor Nagano. Mange av de beste skiområdene ligger i Shiga platået og i nasjonalparken Joshin-Etsu Kogen Kokuritsu -Koen. Innimellom alle disse skisportsstedene ligger mange deilige kursteder.<br /> <br /> De fem sjøene ved Fuji (Fujiyama)<br /> I nærheten av Fuji ligger De fem sjøene. Sjøene er berømte for deres skjønnhet og det er mulig å dyrke vannsport ved sjøene. Det er også forlystelsesparker i området. Man kommer lettest ut til sjøene med buss eller svevebane.<br /> <br /> Kursteder ved Hakone (Fujiyama)<br /> Hvis man er til kursteder og varme kilder bør man reise til Hakone. De fleste kurstedene ligger omkring Ashinoko sjøen. Prøv en seiltur på sjøen eller ta svevebanen eller toget til Owakudani hvor de fleste varme kildene ligger.<br /> <br /> Atombombekuppelen (Genbaku Domu) (Hiroshima)<br /> Genbaku Domu er det siste som står tilbake av vitnesbyrd på atombombens ødeleggelser i 1945. Opprinnelig var bygningen en industrihall, men stålskjelettet som står tilbake minner om en langt vakrere bygning. Bygningens minner om blodig fortid står i skarp kontrast til nåtidens Hiroshima.<br /> <br /> Hiroshima borgen (Hiroshima)<br /> Hiroshima borgen er, som alt annet i Hiroshima, ikke mer enn 55 år gammel. Allikevel lever borgen opp til alle ens fantasier om gammel japansk middelalderborg. I tårnet er det en spennende utstilling med våpen og rustninger.<br /> <br /> Torii porten (Hiroshima)<br /> Torii porten ligger 20 kilometer fra Hiroshima. De fleste vil gjenkjenne den fra bilder og film om Japan uten å kjenne den ved navn. Torii porten er 17 meter høy, bygget av rødt tre og står midt ute i vannet utenfor Shintotempel øyen Miyajima. Nyt også den praktfulle naturen på øyen.<br /> <br /> Fjellet Fuji (Japan)<br /> Fuji er Japans høyeste fjell. Offisielt kan man kun bestige Fuji i juli og august, men det kan i virkeligheten gjøres hele året, selv om det krever en del rutine i vinterhalvåret. Skiltingen er god og man går seg ikke bort.<br /> <br /> Meiji Jingu Tempelet (Tokyo)<br /> Tempelet er imponerende og ligger i en av Tokyos vakre parker og er blant de helligste i Japan. Nyttårsdag besøker mange japanere dette tempelet iført kimonoer. Tempelet er dedikert til keiser Meiji som i sin tid åpnet Japan for omverdenen. Tempelet inneholder mange av keiserens personlige eiendeler. Parkens irishage er blant Japans vakreste.<br /> <br /> Sanjusangendo Tempelet (Kyoto)<br /> Sanjusangendo tempelet i Kyoto er et imponerende stort tempel. Det stod ferdig i 1266 og de 1001 statuene er et av Kamukara periodens mesterverker. Den 15. januar holdes den årlige bueskytingskonkurransen. En tradisjon som stammer fra det 16. århundre.<br /> <br /> Gullpaviljongen (Kyoto)<br /> Kinkakuji (gullpaviljongen) er en av Kyotos absolutte severdigheter. Tempelet ble oppført i det 14. århundre, men måtte gjenoppføres i 1955 etter at en sinnsyk tempelprest brendte det ned. Tempelet er dekket med bladgull og er en nøyaktig kopi av det gamle Kinkakuji.<br /> <br /> Keiserpalasset i Kyoto (Kyoto)<br /> Keiserpalasset er en av de få serverdigheten i Kyotos sentrum. Det nåværende palasset ble oppført i 1855 som erstatning for et tidligere nedbrendt palass. Palasset kan kun besøkes i grupper. Rundvisningene er veldig ettertraktet og det kan anbefales å søke om plass til disse turene allerede en dag i forveien.<br /> <br /> Byen Nara (Nara)<br /> Byen Nara ligger en halv times togtur fra Kyoto. I Nara gjenfinner man Kyotos særlige atmosfære. Byen ble i 710 Japans første permanente hovedstad og har mange velbevarte templer. I Nara Park går det tamme hjort rundt mellom templene.<br /> <br /> Borgen i Himeji (Osaka)<br /> Himeji ligger halvannen times togtur fra Osaka. Byen rommer kanskje Japans vakreste borg som mange nok vil huske fra tv-serien &quot;Shogun&quot;. Den Hvite Hejres Borg (Shirasagi-jo) er et fantastisk byggeri som med sine hvite murer og kurvede tegltak emmer av østens mystikk, innvendig som utvendig. Til borgen er det knyttet to museer og den berømte kirkegården Nagayama.<br /> <br /> Borgen i Osaka (Osaka)<br /> Borgen i Osaka byr på våpen og maleriutstillinger. Borgen er opprinnelig fra det 16. århundre, men har brendt ned et par ganger siden. Borgen er restaurert og har innvendig heis. Ved siden av borgen ligger Osaka bymuseum med samlinger relatert til byens historie samt en mindre keramikksamling.<br /> <br /> Senri Expo Park (Osaka)<br /> Litt nord for Osaka ligger Senri Expo Park hvor Expo ble holdt i 1970. Her finner man blant annet den vakre landskapshagen som ble anlagt i forbindelse med Expo utstillingen. Det hører også et etnologisk museum til parken hvor det utstilles ting og film fra hele verden.<br /> <br /> Bryggeriet i Sapporo (Sapporo)<br /> På Sapporos bryggeri kan alle ølelskere komme på en gratis rundvisning og smake den gode japanske bryggekunst.<br /> <br /> Nakajima Koen parken (Sapporo)<br /> Ønsker man en forsmak på Hokkaidos skjønne natur bør man besøke Nakajima Koen parken. Her kan man slappe av i parkens landskapshage og besøke det historiske tehuset.<br /> <br /> Disneyland i Tokyo (Tokyo)<br /> Disneyland i Tokyo er en tro kopi av Disneyland i California og har de samme attraksjonene. Forlystelsesparken ble innviet i 1983 og har vært en enorm suksess siden. Hvis man ennå ikke har opplevd Disneyland bør man gripe sjansen her. For å unngå trengsel bør man dra der i hverdagene.<br /> <br /> Ginza distriktet (Tokyo)<br /> Litt sydøst for keiserpalasset ligger Ginza distriktet hvor den mest kjøpelystne kan slå seg løs. Her ligger det mange spesialbutikker og stormagasiner. I kvarteret kan man finne mange utenlandske aviser og tollfrie butikker.<br /> <br /> Keiserpalasset (Tokyo)<br /> Keiserpalasset er en av de severdighetene man bør besøke under oppholdet i Tokyo. Det er ikke adgang til selve palasset hvor keiserfamilien bor, men gå en tur i parken og nyt utsikten innover palasset.<br /> <br /> ===Universiteter med samarbeidsavtaler med NTNU===<br /> <br /> ===Annet===<br /> <br /> ==Singapore og Malaysia==<br /> <br /> ===Drillo-fakta===<br /> <br /> ===Nanoteknologi-bedrifter=== <br /> <br /> ===Økonomi===<br /> <br /> En øl kan fås til 20 kr i Singapore i følge pintprice.com, men man må regne med minst det dobbelte mange steder. Snittprisen i Malaysia er 37 kr. <br /> <br /> ===Attraksjoner=== <br /> <br /> ===Universiteter med samarbeidsavtaler med NTNU===<br /> <br /> ===Annet===</div>

Fredrimu http://nanowiki.no/index.php?title=Hovedekskursjon_2010&diff=4153 2009-08-27T12:31:13Z

<p>Fredrimu: /* Nanoteknologi-bedrifter */</p> <hr /> <div>Denne artikkelen inneholder informasjon om hovedekskursjonen til MTNANOs kull 2007. Det er bestemt at reiemålet blir Kinas hovedstad Beijing og omegn.<br /> <br /> <br /> <br /> = Tidsplan =<br /> * 24.03.2009: Deadline for [http://www.timini.no/forum/viewtopic.php?t=1622 idémyldring på forumet]<br /> * 04.05.2009 10:15-12:00, R3: Allmøte med presentasjon av reisemålene og avstemming<br /> * 19.03.2010: Planlagt avreise<br /> * 09.04.2010: Planlagt hjemreise<br /> <br /> =Om Kina som reisemål=<br /> <br /> ===Drillo-fakta===<br /> <br /> ===Nanoteknologi-bedrifter===<br /> <br /> <br /> '''Advapowder'''<br /> Produces nanoscale diamond powder. <br /> <br /> '''AgroMicron (HongKong)'''<br /> The company develops Rapid Early Detection products. These products identify possible pathological threats from bioterrorism to pathogens plaguing global agriculture, animals and people. Test arrays include nanoscale molecule detection techniques.<br /> <br /> '''AlphaNano Technology (Australia(?))'''<br /> A manufacturer of carbon nanotubes and other nanoparticles.<br /> <br /> '''Anson Nanotechnology Group (Hong Kong)'''<br /> Manufactures nanoparticulate antibacterial dressings.<br /> <br /> '''Arry International Group Limited (Hong Kong)'''<br /> Supplier of a wide variety of nano materials, including carbon nanotubes (CNTs) and nano elements as as well as nano oxides (rare earth, metal, and non-metal).<br /> <br /> '''Beijing Chamgo Nano-Tech'''<br /> Manufactures antimicrobial fibers and plastics and nanocomposite materials.<br /> <br /> '''Beijing HuiHaihong Nano-ST'''<br /> The company is mainly engaged in the application research of nanometer-structured material, R&amp;D of new products, technology transfer, technical consultation, technical service, production and management of the newly developed products.<br /> <br /> '''Chengdu Alpha Nano Technology'''<br /> A supplier of carbon nanotubes and various nanopowders.<br /> <br /> '''Chengdu Organic Chemistry Co.'''<br /> Producer of carbon nanotubes.<br /> <br /> '''Chengyin Technology'''<br /> Producer of nanoparticles.<br /> <br /> '''China Rare Metal Material'''<br /> CRM offers a wide range of nanoparticulate specialist metals, oxides, alloys and inorganic chemical compounds.<br /> <br /> '''Chongyi Zhangyuan Tungsten Co., Ltd.'''<br /> Producer of tungsten and tungsten carbide nanopowders.<br /> <br /> '''EnvironmentalCare (Hong Kong)'''<br /> Manufactures nano-TiO2 catalytic surface coating materials.<br /> <br /> '''FCC'''<br /> The company produces 6 series of more than 20 different items bentonite refined products,including NANOLIN series of nanoclay.<br /> <br /> '''Futuresoft Technologies (Beijing)'''<br /> Futuresoft Technologies Inc. is specialized in technologies in plastic materials, their processing equipment and processed products. FTI offers turn-key production systems of wood-plastic composite, extruders, and dies, especially profile dies for wood-plastic, PVC, and TPE. Their polymer nanocomposite technology has been able to make the composite to have much higher property enhancement than those by other technology.<br /> <br /> '''HeFei Kaier Nanometer Technology Development Co.'''<br /> Specializes in nitride and carbide series of nanoparticle ceramic powders.<br /> <br /> '''HeJi, Inc.'''<br /> Producer of carbon nanotubes.<br /> <br /> '''Huizhou TianYi Rare Material'''<br /> Manufacturer of nanopowders.<br /> <br /> '''Jiangsu Changtai Nanometer Material Co, Ltd.'''<br /> Producer of nanoparticles.<br /> <br /> '''Jinri Diamond'''<br /> The company produces diamond abrasives. Among its products are nanodiamond materials.<br /> <br /> '''NaBond'''<br /> Focused on development, manufacture and application of nanomaterials and adhesives.<br /> <br /> '''Nano-Group Holdings'''<br /> Provides nanotechnology applications for the textile and garment industries.<br /> <br /> '''Semiconductor Manufacturing International Corporation (SMIC)'''<br /> SMIC is one of the leading semiconductor foundries in the world and the largest and most advanced foundry in Mainland China, providing integrated circuit manufacturing service at 0.35 micron to 65 nanometer and finer line technologies.<br /> <br /> '''Shanghai ADD Nano-ST'''<br /> Manufactures PTFE nanopowders for printing, dyeing, and cosmetic applications.<br /> <br /> '''ShangHai Allrun Nano Science &amp; Technology'''<br /> Allrun Nano's technologies consist of distinct nanomaterial manufacturing processes, surface treatment technologies of nanomaterial, and its bio-medical application technologies. Allrun Nano has created an integrated platform of nanomaterial technologies that are designed to deliver nanomaterial solutions for market applications.<br /> <br /> '''Shanghai Huzheng Nano Technology'''<br /> Producer of wide range of nanoparticles, coating supplements and finishing agents.<br /> <br /> '''Shanghai Shanghui Nano Science and Technology'''<br /> The company specializes in the R&amp;D, production and distribution of high-tech industrial products of nanomaterials. In possession of its own centre of R&amp;D and integrating production with industrialization, the company cooperates with colleges and scientific institutions with regard to the projects of nanomaterials and technologies.<br /> <br /> '''Shenzen Nano-Technologies Port Co., Ltd.'''<br /> Producer of carbon nanotubes.<br /> <br /> '''Shenzhen JinGangYuan New Material Development'''<br /> The company specializes in developing and manufacturing nanodiamond and other related products.<br /> <br /> '''Shenzhen Junye Nano Material Co.'''<br /> Produces metal nanoparticles.<br /> <br /> '''Shenzhen Nanotechnologies'''<br /> The company is focusing on the R&amp;D, manufacture and application of carbon nanotubes.<br /> <br /> '''Sokang Nano'''<br /> Develops several lines of nanotech product including nano coating, nano coating additive, nano air cleaner module and nano water cleaning module.<br /> <br /> '''Sumi Long Nanotechnology Materials'''<br /> (Site in Chinese) A subsidiary of Sumitomo Osaka Cement, the company develops and manufactures antimagnetic, anti-reflection coatings with nanoparticles.<br /> <br /> '''Sun Nanotech Co, Ltd.'''<br /> Supplier of carbon nanotubes.<br /> <br /> '''Texnology Nano Textile'''<br /> Applies nanocoatings to textile fibers and materials.<br /> <br /> '''TiPE'''<br /> TiPE is a leading nano photocatalyst manufacturer in China, with its proprietary advanced Nano-hydrosynthetic™ technology. TiPE also is the biggest hydrosynthetic photocatalyst manufacturer in China.<br /> <br /> '''TitanPE Technology (Shanghai) Inc.'''<br /> Produces nano photocatalysts.<br /> <br /> '''Yantai Jialong Nano Industry'''<br /> The company conducts research and development of nanomaterials. It is the 863 Program Industrialization Base, Shandong Nanocoating Engineering &amp; technology Research Center and Yantai Nano Engineering &amp; Technology Research Center.<br /> <br /> '''Zhejiang Fenghong Clay Chemicals'''<br /> Engages in research, development, manufacture and trade of refined clay related products such as organoclay rheological additives ornanoclay for polymers.<br /> <br /> '''Zibo ShineSo Chemical New Material'''<br /> ShineSo specializes in the R&amp;D, manufacturing distribution and technical service of advanced ceramic materials including nanopowders.<br /> <br /> ===Økonomi===<br /> <br /> I følge pintprice.com er det store geografiske variasjoner i ølprisene i Kina; fra under 2 kr i Changchun til over 40 kr i Shanghai. I Beijing er prisen ca 10 kr. <br /> <br /> ===Attraksjoner=== <br /> <br /> ===Universiteter med samarbeidsavtaler med NTNU===<br /> <br /> ===Forslag til steder å dra 3.uke===<br /> * Sanya<br /> <br /> Average Data Apr <br /> <br /> Average High (C) 29/31<br /> <br /> Average Low (C) 23/25<br /> <br /> Rain (mm) 30/35<br /> <br /> <br /> [[Bilde:Sanya.jpg]]<br /> <br /> ===Annet===<br /> I Kina selges det ikke tamponger av noe slag. Kilde: Frisør Tango Ulefoss<br /> <br /> =Forslag til reisemål som ble forkastet=<br /> <br /> ==California==<br /> <br /> ===Drillo-fakta===<br /> Hovedstad: Sacramento<br /> <br /> Guvernør: Arnold Schwarzenegger (R)<br /> <br /> ===Nanoteknologi-bedrifter=== <br /> <br /> Silicon Valley ligger den sørlige derlen av San Fransico Bay Area i Northern California og har fått navnet sitt på grunn av områdets høye konsentrasjon av innovative elektronikkbedrifter. Med tiden har dette området blitt et slags symbol på nyskapning, entrepenørskap og ingeniørbragder. Silicon Valley er USAs ledende high-tech industriområde med bedrifter som (med forbehold om at ikke alle er direkte nanorelevante):<br /> *'''Advanced Micro Devices (AMD)'''<br /> *Apple Inc.<br /> *'''Applied Materials'''<br /> *Google<br /> *[http://www.intel.com/ '''Intel''']<br /> *LSI Logic<br /> *'''National Semiconductor'''<br /> *Sun Microsystems<br /> *Asus<br /> *Atari<br /> *Cypress Semiconductor<br /> *Facebook<br /> *'''IBM Almaden Research Center'''<br /> *Opera Software<br /> *Tesla Motors<br /> *'''Sun Power'''<br /> *NASA Ames Research Center<br /> *Quantum Dot Corporation<br /> <br /> ===Økonomi===<br /> *Visum<br /> **Må ha elektronsik pass, for nytt pass 450 NOK (Kilde: politi.no)<br /> **Koster 750 NOK (Kilde: Den amerikanske ambassade)<br /> *Reiseforsikring<br /> **Kan gjøres billig, eller f.eks. Europeiske, verden helår: 1215 NOK<br /> *Flybilletter<br /> **Trondheim - San Francisco apprxo. 7 000 - 8 000 NOK (Kilde: kelkoo.no)<br /> **Oslo - San Francisco ned mot 5 000 NOK (Kilde: kelkoo.no)<br /> *Overnatting<br /> **approx. 200 NOK night^-1 for hostel (Kilde: hostels.com)<br /> *Øl<br /> **25-35 NOK arbitary beer unit^-1. I byen Chico kan man imidlertid få en duggfrisk til under 12 kr (Kilde: pintprice.com).<br /> <br /> ===Attraksjoner===<br /> <br /> *San Fransisco<br /> **Alcatraz<br /> **Golden Gate<br /> **Golden Gate Park<br /> **Myth Busters + lignende serier fra Discovery Channel?<br /> **Twin peaks<br /> *Los Angeles<br /> **Santa Monica Beach<br /> **Venice Beach<br /> **Hollywood<br /> **Long Beach<br /> **Beverly Hills<br /> *San Diego<br /> ** Varme, digge sandstrender<br /> *Tijuana, Mexico<br /> **Beryktet natteliv<br /> *Central Valley<br /> **Sierra Nevada Mountains, 800 miles med turmuligheter<br /> **Kul ørken<br /> *Santa Barbara<br /> ** vakre strender og surfere<br /> <br /> ===Universiteter===<br /> *California Institute of Technology (CALTECH)<br /> **Kavli nanoscience institute driver forskning blant annet innen bionanoteknologi og nanofotinikk<br /> *University of California @ Berkeley, San Diego og Santa Barbara<br /> **Har utvekslingsavtale med NTNU<br /> <br /> ===Annet===<br /> *Infrastruktur<br /> ** lav språkbarriere<br /> ** Relativt bra og billig togtransport innenfor staten, for eksempel har Bay Area Rapid Transit typsisk 15 min ruter mellom San Francisco Peninsula og Oakland, Berkeley, Fremont, Walnut Creek og andre byer i East Bay.<br /> <br /> ==Vest-Europa==<br /> <br /> ===Drillo-fakta===<br /> <br /> ===Nanoteknologi-bedrifter=== <br /> <br /> ===Økonomi===<br /> <br /> Vanlige ølpriser er Frankrike er ca 50 kr i følge pintprice.com. 40 kr er typisk i Barcelona, mens man i Sveits slipper unna med 35 kr.<br /> [[Image:Inter.jpg|left|thumb|500px|]]<br /> <br /> ===Attraksjoner===<br /> *Frankrike<br /> ** Paris!<br /> ** Vinsmaking i Bourgogne, Champagne eller Bordeaux<br /> <br /> ===Universiteter med samarbeidsavtaler med NTNU===<br /> *Frankrike<br /> ** INSA Toulouse<br /> ** UTT<br /> **Université de téchnologie de Compiègne <br /> **INPG - ENSIMAG<br /> **Ecole Superieure d'Ingenieurs de Marseille <br /> **Ecole National Chimie de Paris <br /> **Université de Poitiers <br /> **Institut National Polytechnique de Grenoble<br /> <br /> Bare i Paris er det 7 universiteter, 6 &quot;grandes écoles&quot; og 84 instutisjoner som kommer under den nasjonale handlingsplanen for nanoteknologi i Frankrike.<br /> <br /> ===Annet===<br /> <br /> <br /> ==Japan==<br /> <br /> ===Drillo-fakta===<br /> Hovedstad: Tokyo<br /> <br /> Innbygggertall: 127 millioner<br /> <br /> Språk: Japansk<br /> <br /> ===Nanoteknologi-bedrifter=== <br /> <br /> ===Økonomi===<br /> <br /> Pintprice.com hevder at snittprisen på en øl i Japan er 35 kr. I hovedstaden Tokyo er prisen opp mot 50-lappen. <br /> <br /> ===Attraksjoner===<br /> Byen Nagano (De japanske Alper)<br /> De fleste kjenner Nagano som vertsby for vinter-OL 1998. Byen er den største i området og blant dens fineste severdighet er Zenkoji tempelet som absolutt bør ses hvis man kommer til de japanske alpene.<br /> <br /> Skiområdet (De japanske Alper)<br /> De berømte skisportsstedene ligger et stykke utenfor Nagano. Mange av de beste skiområdene ligger i Shiga platået og i nasjonalparken Joshin-Etsu Kogen Kokuritsu -Koen. Innimellom alle disse skisportsstedene ligger mange deilige kursteder.<br /> <br /> De fem sjøene ved Fuji (Fujiyama)<br /> I nærheten av Fuji ligger De fem sjøene. Sjøene er berømte for deres skjønnhet og det er mulig å dyrke vannsport ved sjøene. Det er også forlystelsesparker i området. Man kommer lettest ut til sjøene med buss eller svevebane.<br /> <br /> Kursteder ved Hakone (Fujiyama)<br /> Hvis man er til kursteder og varme kilder bør man reise til Hakone. De fleste kurstedene ligger omkring Ashinoko sjøen. Prøv en seiltur på sjøen eller ta svevebanen eller toget til Owakudani hvor de fleste varme kildene ligger.<br /> <br /> Atombombekuppelen (Genbaku Domu) (Hiroshima)<br /> Genbaku Domu er det siste som står tilbake av vitnesbyrd på atombombens ødeleggelser i 1945. Opprinnelig var bygningen en industrihall, men stålskjelettet som står tilbake minner om en langt vakrere bygning. Bygningens minner om blodig fortid står i skarp kontrast til nåtidens Hiroshima.<br /> <br /> Hiroshima borgen (Hiroshima)<br /> Hiroshima borgen er, som alt annet i Hiroshima, ikke mer enn 55 år gammel. Allikevel lever borgen opp til alle ens fantasier om gammel japansk middelalderborg. I tårnet er det en spennende utstilling med våpen og rustninger.<br /> <br /> Torii porten (Hiroshima)<br /> Torii porten ligger 20 kilometer fra Hiroshima. De fleste vil gjenkjenne den fra bilder og film om Japan uten å kjenne den ved navn. Torii porten er 17 meter høy, bygget av rødt tre og står midt ute i vannet utenfor Shintotempel øyen Miyajima. Nyt også den praktfulle naturen på øyen.<br /> <br /> Fjellet Fuji (Japan)<br /> Fuji er Japans høyeste fjell. Offisielt kan man kun bestige Fuji i juli og august, men det kan i virkeligheten gjøres hele året, selv om det krever en del rutine i vinterhalvåret. Skiltingen er god og man går seg ikke bort.<br /> <br /> Meiji Jingu Tempelet (Tokyo)<br /> Tempelet er imponerende og ligger i en av Tokyos vakre parker og er blant de helligste i Japan. Nyttårsdag besøker mange japanere dette tempelet iført kimonoer. Tempelet er dedikert til keiser Meiji som i sin tid åpnet Japan for omverdenen. Tempelet inneholder mange av keiserens personlige eiendeler. Parkens irishage er blant Japans vakreste.<br /> <br /> Sanjusangendo Tempelet (Kyoto)<br /> Sanjusangendo tempelet i Kyoto er et imponerende stort tempel. Det stod ferdig i 1266 og de 1001 statuene er et av Kamukara periodens mesterverker. Den 15. januar holdes den årlige bueskytingskonkurransen. En tradisjon som stammer fra det 16. århundre.<br /> <br /> Gullpaviljongen (Kyoto)<br /> Kinkakuji (gullpaviljongen) er en av Kyotos absolutte severdigheter. Tempelet ble oppført i det 14. århundre, men måtte gjenoppføres i 1955 etter at en sinnsyk tempelprest brendte det ned. Tempelet er dekket med bladgull og er en nøyaktig kopi av det gamle Kinkakuji.<br /> <br /> Keiserpalasset i Kyoto (Kyoto)<br /> Keiserpalasset er en av de få serverdigheten i Kyotos sentrum. Det nåværende palasset ble oppført i 1855 som erstatning for et tidligere nedbrendt palass. Palasset kan kun besøkes i grupper. Rundvisningene er veldig ettertraktet og det kan anbefales å søke om plass til disse turene allerede en dag i forveien.<br /> <br /> Byen Nara (Nara)<br /> Byen Nara ligger en halv times togtur fra Kyoto. I Nara gjenfinner man Kyotos særlige atmosfære. Byen ble i 710 Japans første permanente hovedstad og har mange velbevarte templer. I Nara Park går det tamme hjort rundt mellom templene.<br /> <br /> Borgen i Himeji (Osaka)<br /> Himeji ligger halvannen times togtur fra Osaka. Byen rommer kanskje Japans vakreste borg som mange nok vil huske fra tv-serien &quot;Shogun&quot;. Den Hvite Hejres Borg (Shirasagi-jo) er et fantastisk byggeri som med sine hvite murer og kurvede tegltak emmer av østens mystikk, innvendig som utvendig. Til borgen er det knyttet to museer og den berømte kirkegården Nagayama.<br /> <br /> Borgen i Osaka (Osaka)<br /> Borgen i Osaka byr på våpen og maleriutstillinger. Borgen er opprinnelig fra det 16. århundre, men har brendt ned et par ganger siden. Borgen er restaurert og har innvendig heis. Ved siden av borgen ligger Osaka bymuseum med samlinger relatert til byens historie samt en mindre keramikksamling.<br /> <br /> Senri Expo Park (Osaka)<br /> Litt nord for Osaka ligger Senri Expo Park hvor Expo ble holdt i 1970. Her finner man blant annet den vakre landskapshagen som ble anlagt i forbindelse med Expo utstillingen. Det hører også et etnologisk museum til parken hvor det utstilles ting og film fra hele verden.<br /> <br /> Bryggeriet i Sapporo (Sapporo)<br /> På Sapporos bryggeri kan alle ølelskere komme på en gratis rundvisning og smake den gode japanske bryggekunst.<br /> <br /> Nakajima Koen parken (Sapporo)<br /> Ønsker man en forsmak på Hokkaidos skjønne natur bør man besøke Nakajima Koen parken. Her kan man slappe av i parkens landskapshage og besøke det historiske tehuset.<br /> <br /> Disneyland i Tokyo (Tokyo)<br /> Disneyland i Tokyo er en tro kopi av Disneyland i California og har de samme attraksjonene. Forlystelsesparken ble innviet i 1983 og har vært en enorm suksess siden. Hvis man ennå ikke har opplevd Disneyland bør man gripe sjansen her. For å unngå trengsel bør man dra der i hverdagene.<br /> <br /> Ginza distriktet (Tokyo)<br /> Litt sydøst for keiserpalasset ligger Ginza distriktet hvor den mest kjøpelystne kan slå seg løs. Her ligger det mange spesialbutikker og stormagasiner. I kvarteret kan man finne mange utenlandske aviser og tollfrie butikker.<br /> <br /> Keiserpalasset (Tokyo)<br /> Keiserpalasset er en av de severdighetene man bør besøke under oppholdet i Tokyo. Det er ikke adgang til selve palasset hvor keiserfamilien bor, men gå en tur i parken og nyt utsikten innover palasset.<br /> <br /> ===Universiteter med samarbeidsavtaler med NTNU===<br /> <br /> ===Annet===<br /> <br /> ==Singapore og Malaysia==<br /> <br /> ===Drillo-fakta===<br /> <br /> ===Nanoteknologi-bedrifter=== <br /> <br /> ===Økonomi===<br /> <br /> En øl kan fås til 20 kr i Singapore i følge pintprice.com, men man må regne med minst det dobbelte mange steder. Snittprisen i Malaysia er 37 kr. <br /> <br /> ===Attraksjoner=== <br /> <br /> ===Universiteter med samarbeidsavtaler med NTNU===<br /> <br /> ===Annet===</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4109 2009-05-26T11:42:48Z

<p>Fredrimu: /* Contact mode */</p> <hr /> <div>==Short facts==<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Tip materials used: diamond, tungsten, silicon. Silicon nitride - high elastic rigidity.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ==Basic setup and components==<br /> <br /> *AFM often mounted on rigid base with high damping capacity. <br /> *Adjustable sample stage.<br /> *<br /> <br /> Movement:<br /> *X-Y: Applying voltage of opposite signs across diagonal segments of piezoelectric tube. Will cause it to bend.<br /> *Z: Apply voltage on tube that contracts or expands axial length.<br /> <br /> Split photo detector:<br /> <br /> *Solid state laser<br /> *The deflected cantilever reflects a laser beam from two points on the cantilever (before and after deflection) and two beams are sent to the detector. The signal generated depends on the proporiton of light falling on each half of the photodiode. (Noen som kan forklare dette bedre?)<br /> *Can also measure phase shifts.<br /> <br /> Data collection:<br /> <br /> *Artifacts! Non-linearity in piezoelectric response. Sample surface must be coplanar with x-y scan of probe tip.<br /> <br /> ==Modes of operation==<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model (surface forces) lies behind different modes:<br /> *Strongly affected by surface adsorbates and gaseous/liquid environment.<br /> <br /> ===Contact mode=== <br /> In the contact region of the potential energy curve, repulsive forces dominate.<br /> <br /> Two sub-modes: <br /> *Set height constant and measure repulsive force. <br /> *Set repulsive force constant and measure height.<br /> <br /> Artifacts that can be removed when operating in contact mode:<br /> *Capilliary attraction from films of moisture (under atmospheric conditions).<br /> *Electrostatic charging of surface<br /> <br /> ===Tapping mode=== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude. Force on probe tip changes sign during cycle. Phase image extremly sensitive to elastic properties.<br /> <br /> ===Non-contact mode=== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.<br /> <br /> Maximum deflection sensitivity: Thin v-shaped cantilever. Si nitride tip minimizes damage to the tip. Soft samples: Constant pre-set cantilever deflection. (Kan noen utdype/omformulere siste setning?)<br /> <br /> [[Kategori: teknikker i tools]]</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4108 2009-05-26T11:28:56Z

<p>Fredrimu: /* Short facts */</p> <hr /> <div>==Short facts==<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Tip materials used: diamond, tungsten, silicon. Silicon nitride - high elastic rigidity.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ==Basic setup and components==<br /> <br /> *AFM often mounted on rigid base with high damping capacity. <br /> *Adjustable sample stage.<br /> *<br /> <br /> Movement:<br /> *X-Y: Applying voltage of opposite signs across diagonal segments of piezoelectric tube. Will cause it to bend.<br /> *Z: Apply voltage on tube that contracts or expands axial length.<br /> <br /> Split photo detector:<br /> <br /> *Solid state laser<br /> *The deflected cantilever reflects a laser beam from two points on the cantilever (before and after deflection) and two beams are sent to the detector. The signal generated depends on the proporiton of light falling on each half of the photodiode. (Noen som kan forklare dette bedre?)<br /> *Can also measure phase shifts.<br /> <br /> Data collection:<br /> <br /> *Artifacts! Non-linearity in piezoelectric response. Sample surface must be coplanar with x-y scan of probe tip.<br /> <br /> ==Modes of operation==<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model (surface forces) lies behind different modes:<br /> *Strongly affected by surface adsorbates and gaseous/liquid environment.<br /> <br /> ===Contact mode=== <br /> In the contact region of the potential energy curve, repulsive forces dominate. This mode has the highest resolution.<br /> <br /> Two sub-modes: <br /> *Set height constant and measure repulsive force. <br /> *Set repulsive force constant and measure height.<br /> <br /> Artifacts that can be removed when operating in contact mode:<br /> *Capilliary attraction from films of moisture (under atmospheric conditions).<br /> *Electrostatic charging of surface<br /> <br /> ===Tapping mode=== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude. Force on probe tip changes sign during cycle. Phase image extremly sensitive to elastic properties.<br /> <br /> ===Non-contact mode=== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.<br /> <br /> Maximum deflection sensitivity: Thin v-shaped cantilever. Si nitride tip minimizes damage to the tip. Soft samples: Constant pre-set cantilever deflection. (Kan noen utdype/omformulere siste setning?)<br /> <br /> [[Kategori: teknikker i tools]]</div>

Fredrimu http://nanowiki.no/index.php?title=Scanning_Tunneling_Microscopy&diff=4080 2009-05-24T12:55:14Z

<p>Fredrimu: /* Principle */</p> <hr /> <div>==Fun facts==<br /> *High vacuum is not necessary, but often used.<br /> *Performed on conducting and semi-conducting materials.<br /> <br /> ==Principle==<br /> A voltage is applied on the probe tip and it is brought close to the surface of the sample. The probe measures the tunneling current that passes from the sample to the tip. How can there be a tuneling current? In classical physics, if a particle would encounter an energy barrier higher than its own energy, it would bounce back. But tunneling is a quantum effect. When an electron meets an energy barrier higher than its own energy it will penetrate the energy barrier, and if the barrier is thin enough (which in this case means a small distance between the probe and the suface) it will have a chance to go through the barrier. This probability of tunneling decreases exponentially with the distance from the tip of the probe to the surface. The tunneling current is also dependent on the density of states of the molecules on the surface of the sample.<br /> <br /> The tunneling current is therefore dependent on the density of states at the sample surface (work function) and exponentially dependent of the distance.<br /> <br /> [[Kategori: Teknikker i tools]]<br /> <br /> ==Operation modes==<br /> <br /> *Constant z, changes in tunneling current is monitored. Interpreted as either change in work function or probe-sample separation.<br /> *Tunneling current pre-selected and varying z to keep electron field emission current constant. Changes in z interpreted as change in topography.<br /> *Scan bias voltage at each x-y pixel. Obtain local value for voltage dependence of i(V) for both given tip-sample separation and x-y location. Slope of i(V) can be interpreted in terms of local density of states. Results in excellent atomic resolution of surface.</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4079 2009-05-24T12:34:40Z

<p>Fredrimu: /* Tapping mode */</p> <hr /> <div>==Short facts==<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ==Basic setup and components==<br /> <br /> *AFM often mounted on rigid base with high damping capacity. <br /> *Adjustable sample stage.<br /> *<br /> <br /> Movement:<br /> *X-Y: Applying voltage of opposite signs across diagonal segments of piezoelectric tube. Will cause it to bend.<br /> *Z: Apply voltage on tube that contracts or expands axial length.<br /> <br /> Split photo detector:<br /> <br /> *Solid state laser<br /> *The deflected cantilever reflects a laser beam from two points on the cantilever (before and after deflection) and two beams are sent to the detector. The signal generated depends on the proporiton of light falling on each half of the photodiode. (Noen som kan forklare dette bedre?)<br /> *Can also measure phase shifts.<br /> <br /> Data collection:<br /> <br /> *Artifacts! Non-linearity in piezoelectric response. Sample surface must be coplanar with x-y scan of probe tip.<br /> <br /> ==Modes of operation==<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model (surface forces) lies behind different modes:<br /> *Strongly affected by surface adsorbates and gaseous/liquid environment.<br /> <br /> ===Contact mode=== <br /> In the contact region of the potential energy curve, repulsive forces dominate. This mode has the highest resolution.<br /> <br /> Two sub-modes: <br /> *Set height constant and measure repulsive force. <br /> *Set repulsive force constant and measure height.<br /> <br /> Artifacts that can be removed when operating in contact mode:<br /> *Capilliary attraction from films of moisture (under atmospheric conditions).<br /> *Electrostatic charging of surface<br /> <br /> ===Tapping mode=== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude. Force on probe tip changes sign during cycle. Phase image extremly sensitive to elastic properties.<br /> <br /> ===Non-contact mode=== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.<br /> <br /> Maximum deflection sensitivity: Thin v-shaped cantilever. Si nitride tip minimizes damage to the tip. Soft samples: Constant pre-set cantilever deflection. (Kan noen utdype/omformulere siste setning?)<br /> <br /> [[Kategori: teknikker i tools]]</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4062 2009-05-24T11:26:47Z

<p>Fredrimu: /* Contact mode */</p> <hr /> <div>==Short facts==<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ==Basic setup and components==<br /> <br /> *AFM often mounted on rigid base with high damping capacity. <br /> *Adjustable sample stage.<br /> *<br /> <br /> Movement:<br /> *X-Y: Applying voltage of opposite signs across diagonal segments of piezoelectric tube. Will cause it to bend.<br /> *Z: Apply voltage on tube that contracts or expands axial length.<br /> <br /> Split photo detector:<br /> <br /> *Solid state laser<br /> *The deflected cantilever reflects a laser beam from two points on the cantilever (before and after deflection) and two beams are sent to the detector. The signal generated depends on the proporiton of light falling on each half of the photodiode. (Noen som kan forklare dette bedre?)<br /> *Can also measure phase shifts.<br /> <br /> Data collection:<br /> <br /> *Artifacts! Non-linearity in piezoelectric response. Sample surface must be coplanar with x-y scan of probe tip.<br /> <br /> ==Modes of operation==<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model (surface forces) lies behind different modes:<br /> *Strongly affected by surface adsorbates and gaseous/liquid environment.<br /> <br /> ===Contact mode=== <br /> In the contact region of the potential energy curve, repulsive forces dominate. This mode has the highest resolution.<br /> <br /> Two sub-modes: <br /> *Set height constant and measure repulsive force. <br /> *Set repulsive force constant and measure height.<br /> <br /> Artifacts that can be removed when operating in contact mode:<br /> *Capilliary attraction from films of moisture (under atmospheric conditions).<br /> *Electrostatic charging of surface<br /> <br /> ===Tapping mode=== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude.<br /> <br /> ===Non-contact mode=== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.<br /> <br /> Maximum deflection sensitivity: Thin v-shaped cantilever. Si nitride tip minimizes damage to the tip. Soft samples: Constant pre-set cantilever deflection. (Kan noen utdype/omformulere siste setning?)<br /> <br /> [[Kategori: teknikker i tools]]</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4061 2009-05-24T11:24:11Z

<p>Fredrimu: /* Modes of operation */</p> <hr /> <div>==Short facts==<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ==Basic setup and components==<br /> <br /> *AFM often mounted on rigid base with high damping capacity. <br /> *Adjustable sample stage.<br /> *<br /> <br /> Movement:<br /> *X-Y: Applying voltage of opposite signs across diagonal segments of piezoelectric tube. Will cause it to bend.<br /> *Z: Apply voltage on tube that contracts or expands axial length.<br /> <br /> Split photo detector:<br /> <br /> *Solid state laser<br /> *The deflected cantilever reflects a laser beam from two points on the cantilever (before and after deflection) and two beams are sent to the detector. The signal generated depends on the proporiton of light falling on each half of the photodiode. (Noen som kan forklare dette bedre?)<br /> *Can also measure phase shifts.<br /> <br /> Data collection:<br /> <br /> *Artifacts! Non-linearity in piezoelectric response. Sample surface must be coplanar with x-y scan of probe tip.<br /> <br /> ==Modes of operation==<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model (surface forces) lies behind different modes:<br /> *Strongly affected by surface adsorbates and gaseous/liquid environment.<br /> <br /> ===Contact mode=== <br /> In the contact region of the potential energy curve, repulsive forces dominate. This mode has the highest resolution.<br /> <br /> Two sub-modes: <br /> *Set height constant and measure repulsive force. <br /> *Set repulsive force constant and measure height.<br /> <br /> ===Tapping mode=== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude.<br /> <br /> ===Non-contact mode=== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.<br /> <br /> Maximum deflection sensitivity: Thin v-shaped cantilever. Si nitride tip minimizes damage to the tip. Soft samples: Constant pre-set cantilever deflection. (Kan noen utdype/omformulere siste setning?)<br /> <br /> [[Kategori: teknikker i tools]]</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4060 2009-05-24T11:15:56Z

<p>Fredrimu: /* Basic setup and components */</p> <hr /> <div>==Short facts==<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ==Basic setup and components==<br /> <br /> *AFM often mounted on rigid base with high damping capacity. <br /> *Adjustable sample stage.<br /> *<br /> <br /> Movement:<br /> *X-Y: Applying voltage of opposite signs across diagonal segments of piezoelectric tube. Will cause it to bend.<br /> *Z: Apply voltage on tube that contracts or expands axial length.<br /> <br /> Split photo detector:<br /> <br /> *Solid state laser<br /> *The deflected cantilever reflects a laser beam from two points on the cantilever (before and after deflection) and two beams are sent to the detector. The signal generated depends on the proporiton of light falling on each half of the photodiode. (Noen som kan forklare dette bedre?)<br /> *Can also measure phase shifts.<br /> <br /> Data collection:<br /> <br /> *Artifacts! Non-linearity in piezoelectric response. Sample surface must be coplanar with x-y scan of probe tip.<br /> <br /> ==Modes of operation==<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model (surface forces) lies behind different modes:<br /> *Strongly affected by surface adsorbates and gaseous/liquid environment.<br /> <br /> ===Contact mode=== <br /> In the contact region of the potential energy curve, repulsive forces dominate. This mode has the highest resolution.<br /> <br /> Two sub-modes: <br /> *Set height constant and measure repulsive force. <br /> *Set repulsive force constant and measure height.<br /> <br /> ===Tapping mode=== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude.<br /> <br /> ===Non-contact mode=== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.<br /> <br /> [[Kategori: teknikker i tools]]</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4059 2009-05-24T11:10:55Z

<p>Fredrimu: /* Basic setup and components */</p> <hr /> <div>==Short facts==<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ==Basic setup and components==<br /> <br /> *AFM often mounted on rigid base with high damping capacity. <br /> *Adjustable sample stage.<br /> *<br /> <br /> Movement:<br /> *X-Y: Applying voltage of opposite signs across diagonal segments of piezoelectric tube. Will cause it to bend.<br /> *Z: Apply voltage on tube that contracts or expands axial length.<br /> <br /> Split photo detector:<br /> <br /> *Solid state laser<br /> *The deflected cantilever reflects a laser beam from two points on the cantilever (before and after deflection) and two beams are sent to the detector. The signal generated depends on the proporiton of light falling on each half of the photodiode. (Noen som kan forklare dette bedre?)<br /> <br /> ==Modes of operation==<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model (surface forces) lies behind different modes:<br /> *Strongly affected by surface adsorbates and gaseous/liquid environment.<br /> <br /> ===Contact mode=== <br /> In the contact region of the potential energy curve, repulsive forces dominate. This mode has the highest resolution.<br /> <br /> Two sub-modes: <br /> *Set height constant and measure repulsive force. <br /> *Set repulsive force constant and measure height.<br /> <br /> ===Tapping mode=== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude.<br /> <br /> ===Non-contact mode=== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.<br /> <br /> [[Kategori: teknikker i tools]]</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4058 2009-05-24T11:02:05Z

<p>Fredrimu: /* Basic setup */</p> <hr /> <div>==Short facts==<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ==Basic setup and components==<br /> <br /> *AFM often mounted on rigid base with high damping capacity. <br /> *Adjustable sample stage.<br /> *<br /> <br /> Movement:<br /> *X-Y: Applying voltage of opposite signs across diagonal segments of piezoelectric tube. Will cause it to bend.<br /> *Z: Apply voltage on tube that contracts or expands axial length.<br /> <br /> ==Modes of operation==<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model (surface forces) lies behind different modes:<br /> *Strongly affected by surface adsorbates and gaseous/liquid environment.<br /> <br /> ===Contact mode=== <br /> In the contact region of the potential energy curve, repulsive forces dominate. This mode has the highest resolution.<br /> <br /> Two sub-modes: <br /> *Set height constant and measure repulsive force. <br /> *Set repulsive force constant and measure height.<br /> <br /> ===Tapping mode=== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude.<br /> <br /> ===Non-contact mode=== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.<br /> <br /> [[Kategori: teknikker i tools]]</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4057 2009-05-24T11:01:33Z

<p>Fredrimu: /* Fun facts */</p> <hr /> <div>==Short facts==<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ==Basic setup==<br /> <br /> *AFM often mounted on rigid base with high damping capacity. <br /> *Adjustable sample stage.<br /> *<br /> <br /> Movement:<br /> *X-Y: Applying voltage of opposite signs across diagonal segments of piezoelectric tube. Will cause it to bend.<br /> *Z: Apply voltage on tube that contracts or expands axial length.<br /> <br /> ==Modes of operation==<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model (surface forces) lies behind different modes:<br /> *Strongly affected by surface adsorbates and gaseous/liquid environment.<br /> <br /> ===Contact mode=== <br /> In the contact region of the potential energy curve, repulsive forces dominate. This mode has the highest resolution.<br /> <br /> Two sub-modes: <br /> *Set height constant and measure repulsive force. <br /> *Set repulsive force constant and measure height.<br /> <br /> ===Tapping mode=== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude.<br /> <br /> ===Non-contact mode=== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.<br /> <br /> [[Kategori: teknikker i tools]]</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4056 2009-05-24T10:49:04Z

<p>Fredrimu: </p> <hr /> <div>==Fun facts==<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ==Basic setup==<br /> <br /> *AFM often mounted on rigid base with high damping capacity. <br /> *Adjustable sample stage.<br /> *<br /> <br /> Movement:<br /> *X-Y: Applying voltage of opposite signs across diagonal segments of piezoelectric tube. Will cause it to bend.<br /> *Z: Apply voltage on tube that contracts or expands axial length.<br /> <br /> ==Modes of operation==<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model (surface forces) lies behind different modes:<br /> *Strongly affected by surface adsorbates and gaseous/liquid environment.<br /> <br /> ===Contact mode=== <br /> In the contact region of the potential energy curve, repulsive forces dominate. This mode has the highest resolution.<br /> <br /> Two sub-modes: <br /> *Set height constant and measure repulsive force. <br /> *Set repulsive force constant and measure height.<br /> <br /> ===Tapping mode=== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude.<br /> <br /> ===Non-contact mode=== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.<br /> <br /> [[Kategori: teknikker i tools]]</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4055 2009-05-24T10:37:17Z

<p>Fredrimu: </p> <hr /> <div>==Fun facts==<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> <br /> ==Modes of operation==<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model (surface forces) lies behind different modes:<br /> *Strongly affected by surface adsorbates and gaseous/liquid environment.<br /> <br /> ===Contact mode=== <br /> In the contact region of the potential energy curve, repulsive forces dominate. This mode has the highest resolution.<br /> <br /> Two sub-modes: <br /> *Set height constant and measure repulsive force. <br /> *Set repulsive force constant and measure height.<br /> <br /> ===Tapping mode=== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude.<br /> <br /> ===Non-contact mode=== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.<br /> <br /> [[Kategori: teknikker i tools]]</div>

Fredrimu http://nanowiki.no/index.php?title=Surface_Probe_Microscopy&diff=4054 2009-05-24T10:34:37Z

<p>Fredrimu: /* Surface forces */</p> <hr /> <div>Scaning probe microscopy is a field where microstructural information can be obtained by bringing a sharp, needle-shaped solid probe into close proximity to the surface we want to study. This method can give information about the surface structure and surface properties.<br /> <br /> ==Surface forces==<br /> <br /> Three interaction zones:<br /> *Non-contact zone: Only long range forces are experienced. Usually attractive. Coulomb forces - strongest long range forces (can be repulsive as well).<br /> *Semi-contact region: Similar magnitude of repulsive and attractive forces.<br /> *Contact zone: Distances smaller than the distance at which the potential energy is zero. Attractive forces are negligible. Short range repulsive forces dominate.<br /> <br /> The forces:<br /> * Strong long-range forces: Coulomb forces<br /> * Shorter distances: Van der Waals (kålloidal kemmistri!) These forces decay rapidly, with &lt;math&gt;f \propto d^{-7}&lt;/math&gt;<br /> * Strong short range forces: Overlapping of electron shells (steric hindrance), Debye/diffuse double layers for example.<br /> <br /> ==Resolution==<br /> The probe tip radius limits the resolution of the image and it will be at least one order of magnitude bigger than the atom spacings.<br /> But it can still give atomic resolution.<br /> <br /> == Lenker ==<br /> #[[AFM]]<br /> #[[STM]]<br /> #[[Field Ion Microscopy and Atom probe tomography]]<br /> <br /> [[Kategori: Teknikker i tools]]</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4053 2009-05-24T10:27:45Z

<p>Fredrimu: /* Modes of operation */</p> <hr /> <div>===Fun facts===<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ===Modes of operation===<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model (surface forces) lies behind different modes:<br /> *Strongly affected by surface adsorbates and gaseous/liquid environment.<br /> <br /> ==Contact mode== <br /> In the contact region of the potential energy curve, repulsive forces dominate. This mode has the highest resolution.<br /> <br /> Two sub-modes: <br /> *Set height constant and measure repulsive force. <br /> *Set repulsive force constant and measure height.<br /> <br /> ==Tapping mode== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude.<br /> <br /> ==Non-contact mode== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.<br /> <br /> [[Kategori: teknikker i tools]]</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4052 2009-05-24T10:19:49Z

<p>Fredrimu: /* Modes of operation */</p> <hr /> <div>===Fun facts===<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ===Modes of operation===<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model (surface forces) lies behind different modes:<br /> *Strongly affected by surface adsorbates and gaseous/liquid environment.<br /> <br /> <br /> Three interaction zones:<br /> *Non-contact zone: Only long range forces are experienced. Usually attractive. Coulomb forces - strongest long range forces (can be repulsive as well).<br /> *Semi-contact region: Similar magnitude of repulsive and attractive forces.<br /> *Contact zone: Attractive forces are negligible. Short range repulsive forces dominate.<br /> <br /> The forces:<br /> * Strong long-range forces: Coulomb forces<br /> * Shorter distances: Van der Waals (kålloidal kemmistri!) These forces decay rapidly, with &lt;math&gt;f \propto d^{-7}&lt;/math&gt;<br /> * Strong short range forces: Overlapping of electron shells.<br /> <br /> ==Contact mode== <br /> In the contact region of the potential energy curve, repulsive forces dominate. This mode has the highest resolution.<br /> <br /> Two sub-modes: <br /> *Set height constant and measure repulsive force. <br /> *Set repulsive force constant and measure height.<br /> <br /> ==Tapping mode== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude.<br /> <br /> ==Non-contact mode== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.<br /> <br /> [[Kategori: teknikker i tools]]</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4038 2009-05-24T09:26:52Z

<p>Fredrimu: /* Contact mode */</p> <hr /> <div>===Fun facts===<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ===Modes of operation===<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model lies behind different modes:<br /> * Strong long-range forces: Coulomb forces<br /> * Shorter distances: Van der Waals (kålloidal kemmistri!) These forces decay rapidly, with &lt;math&gt;f \propto d^{-7}&lt;/math&gt;<br /> * Strong short range forces: Overlapping of electron shells.<br /> <br /> ==Contact mode== <br /> In the contact region of the potential energy curve, repulsive forces dominate. This mode has the highest resolution.<br /> <br /> Two sub-modes: <br /> *Set height constant and measure repulsive force. <br /> *Set repulsive force constant and measure height.<br /> <br /> ==Tapping mode== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude.<br /> <br /> ==Non-contact mode== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4035 2009-05-24T09:24:19Z

<p>Fredrimu: /* Contact mode */</p> <hr /> <div>===Fun facts===<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ===Modes of operation===<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model lies behind different modes:<br /> * Strong long-range forces: Coulomb forces<br /> * Shorter distances: Van der Waals (kålloidal kemmistri!) These forces decay rapidly, with &lt;math&gt;f \propto d^{-7}&lt;/math&gt;<br /> * Strong short range forces: Overlapping of electron shells.<br /> <br /> ==Contact mode== <br /> In the contact region of the potential energy curve, repulsive forces dominate. This mode has the best resolution.<br /> <br /> Two sub-modes: <br /> *Set height constant and measure repulsive force. <br /> *Set force constant and measure height.<br /> <br /> ==Tapping mode== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude.<br /> <br /> ==Non-contact mode== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4034 2009-05-24T09:22:48Z

<p>Fredrimu: /* Contact mode */</p> <hr /> <div>===Fun facts===<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ===Modes of operation===<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model lies behind different modes:<br /> * Strong long-range forces: Coulomb forces<br /> * Shorter distances: Van der Waals (kålloidal kemmistri!) These forces decay rapidly, with &lt;math&gt;f \propto d^{-7}&lt;/math&gt;<br /> * Strong short range forces: Overlapping of electron shells.<br /> <br /> ==Contact mode== <br /> In the contact region of the potential energy curve, repulsive forces dominate. Two sub-modes: Set height constant and measure repulsive force or set force constant and measure height. This mode has the best resolution.<br /> <br /> ==Tapping mode== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude.<br /> <br /> ==Non-contact mode== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4033 2009-05-24T09:19:48Z

<p>Fredrimu: /* Modes of operation */</p> <hr /> <div>===Fun facts===<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ===Modes of operation===<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model lies behind different modes:<br /> * Strong long-range forces: Coulomb forces<br /> * Shorter distances: Van der Waals (kålloidal kemmistri!) These forces decay rapidly, with &lt;math&gt;f \propto d^{-7}&lt;/math&gt;<br /> * Strong short range forces: Overlapping of electron shells.<br /> <br /> ==Contact mode== <br /> In the contact region of the potential energy curve, repulsive forces dominate. Two sub-modes: Set height constant and measure repulsive force or set force constant and measure height.<br /> <br /> ==Tapping mode== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude.<br /> <br /> ==Non-contact mode== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4031 2009-05-24T09:18:56Z

<p>Fredrimu: /* Modes of operation */</p> <hr /> <div>===Fun facts===<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ===Modes of operation===<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model lies behind different modes:<br /> * Strong long-range forces: Coulomb forces<br /> * Shorter distances: Van der Waals (kålloidal kemmistri!) These forces decay rapidly, with &lt;math&gt;f \propto d^{-7}&lt;/math&gt;<br /> <br /> ==Contact mode== <br /> In the contact region of the potential energy curve, repulsive forces dominate. Two sub-modes: Set height constant and measure repulsive force or set force constant and measure height.<br /> <br /> ==Tapping mode== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude.<br /> <br /> ==Non-contact mode== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4030 2009-05-24T09:18:05Z

<p>Fredrimu: /* Modes of operation */</p> <hr /> <div>===Fun facts===<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ===Modes of operation===<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model lies behind different modes:<br /> * Strong long-range forces: Coulomb forces<br /> * Shorter distances: Van der Waals (kålloidal kemmistri!) These forces decay rapidly, with &lt;math&gt;f \propto d^-7&lt;/math&gt;<br /> <br /> ==Contact mode== <br /> In the contact region of the potential energy curve, repulsive forces dominate. Two sub-modes: Set height constant and measure repulsive force or set force constant and measure height.<br /> <br /> ==Tapping mode== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude.<br /> <br /> ==Non-contact mode== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4028 2009-05-24T09:16:58Z

<p>Fredrimu: /* Modes of operation */</p> <hr /> <div>===Fun facts===<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ===Modes of operation===<br /> It is the displacement of the probe tip at the end of the cantilever that is measured. The modes have different resolution (can someone explain this?). Problem and material determines which mode is used.<br /> <br /> Interaction model lies behind different modes:<br /> * Strong long-range forces: Coulomb forces<br /> * Shorter distances: Van der Waals (kålloidal kemmistri!) These forces decay rapidly, with &lt;math&gt;f \\propto d^-7&lt;/math&gt;<br /> <br /> ==Contact mode== <br /> In the contact region of the potential energy curve, repulsive forces dominate. Two sub-modes: Set height constant and measure repulsive force or set force constant and measure height.<br /> <br /> ==Tapping mode== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude.<br /> <br /> ==Non-contact mode== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4027 2009-05-24T09:09:59Z

<p>Fredrimu: /* Tapping mode */</p> <hr /> <div>===Fun facts===<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ===Modes of operation===<br /> It is the displacement of the probe tip at the end of the cantilever that is measured.<br /> <br /> ==Contact mode== <br /> In the contact region of the potential energy curve, repulsive forces dominate. Two sub-modes: Set height constant and measure repulsive force or set force constant and measure height.<br /> <br /> ==Tapping mode== <br /> In the semi-contact region of the potential energy curve. Attractive and repulsive forces have similar magnitude.<br /> <br /> ==Non-contact mode== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.</div>

Fredrimu http://nanowiki.no/index.php?title=Atomic_Force_Microscopy&diff=4026 2009-05-24T09:02:38Z

<p>Fredrimu: /* Fun facts */</p> <hr /> <div>===Fun facts===<br /> *High vacuum is not necessary.<br /> *Piezoelectric position control system.<br /> *The cantilever: V-shaped or single beam. V-shaped: high deflection sensitivity, not sensitive to torque. Single beam: vice-versa.<br /> *Material used: diamond, tungsten, silicon.<br /> *Artifacts: drift, non-linear hysteresis of piezoelectric.<br /> <br /> ===Modes of operation===<br /> It is the displacement of the probe tip at the end of the cantilever that is measured.<br /> <br /> ==Contact mode== <br /> In the contact region of the potential energy curve, repulsive forces dominate. Two sub-modes: Set height constant and measure repulsive force or set force constant and measure height.<br /> <br /> ==Tapping mode== <br /> In the semi-contact region of the potential energy curve.<br /> <br /> ==Non-contact mode== <br /> In the non-contact region of the potential energy curve, attractive forces dominate and are measured. What is observed is a an increase in the amplitude of the oscillations of the vibrating probe, translated into a change in attractive forces.</div>

Fredrimu http://nanowiki.no/index.php?title=Scanning_Tunneling_Microscopy&diff=4025 2009-05-24T08:59:30Z

<p>Fredrimu: /* Fun facts */</p> <hr /> <div>==Fun facts==<br /> *High vacuum is not necessary, but often used.<br /> *Performed on conducting and semi-conducting materials.<br /> <br /> ==Principe==<br /> A voltage is applied on the probe tip and it is brought close to the surface of the sample. The probe measures the tunneling current that passes from the sample to the tip. How can there be a tuneling current? In classical physics, if a particle would encounter an energy barrier higher than its own energy, it would bounce back. But tunneling is a quantum effect. When an electron meets an energy barrier higher than its own energy it will penetrate the energy barrier, and if the barrier is thin enough (which in this case means a small distance between the probe and the suface) it will have a chance to go through the barrier. This probability of tunneling decreases exponentially with the distance from the tip of the probe to the surface. The tunneling current is also dependent on the density of states of the molecules on the surface of the sample.</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3458 2009-03-31T23:01:30Z

<p>Fredrimu: /* Distribution of entered nanoparticles */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach $1000,000,000,000 USD by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach $5800000000 by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulation of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk) has postulated, and it is to be found elsewhere, a definition of nanotechnology as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have similar effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters that have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in foods.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingredients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach their destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions have similar properties to emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions is that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound. PEG (polyethylene glycol) is often used here. A PLA-PEG diblock compound can be able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or environmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to the food product.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface is coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions on the food product. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsion between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology. Many biological compounds, for instance polysaccharides and proteins, can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging. Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known how these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis (the outermost layer of the skin) could protect against nanoparticles. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm in diameter) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanoparticles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> <br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Some experiments show that anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it consists of a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can reach the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3457 2009-03-31T23:00:18Z

<p>Fredrimu: /* Ingestion */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach $1000,000,000,000 USD by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach $5800000000 by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulation of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk) has postulated, and it is to be found elsewhere, a definition of nanotechnology as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have similar effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters that have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in foods.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingredients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach their destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions have similar properties to emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions is that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound. PEG (polyethylene glycol) is often used here. A PLA-PEG diblock compound can be able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or environmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to the food product.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface is coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions on the food product. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsion between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology. Many biological compounds, for instance polysaccharides and proteins, can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging. Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known how these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis (the outermost layer of the skin) could protect against nanoparticles. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm in diameter) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanoparticles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> <br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Some experiments show that anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it consists of a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3456 2009-03-31T22:58:42Z

<p>Fredrimu: /* Inhalation */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach $1000,000,000,000 USD by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach $5800000000 by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulation of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk) has postulated, and it is to be found elsewhere, a definition of nanotechnology as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have similar effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters that have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in foods.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingredients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach their destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions have similar properties to emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions is that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound. PEG (polyethylene glycol) is often used here. A PLA-PEG diblock compound can be able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or environmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to the food product.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface is coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions on the food product. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsion between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology. Many biological compounds, for instance polysaccharides and proteins, can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging. Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known how these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis (the outermost layer of the skin) could protect against nanoparticles. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm in diameter) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanoparticles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> <br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3455 2009-03-31T22:56:58Z

<p>Fredrimu: /* Dermal exposure */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach $1000,000,000,000 USD by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach $5800000000 by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulation of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk) has postulated, and it is to be found elsewhere, a definition of nanotechnology as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have similar effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters that have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in foods.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingredients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach their destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions have similar properties to emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions is that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound. PEG (polyethylene glycol) is often used here. A PLA-PEG diblock compound can be able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or environmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to the food product.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface is coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions on the food product. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsion between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology. Many biological compounds, for instance polysaccharides and proteins, can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging. Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known how these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis (the outermost layer of the skin) could protect against nanoparticles. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm in diameter) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3454 2009-03-31T22:55:29Z

<p>Fredrimu: /* Health risks */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach $1000,000,000,000 USD by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach $5800000000 by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulation of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk) has postulated, and it is to be found elsewhere, a definition of nanotechnology as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have similar effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters that have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in foods.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingredients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach their destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions have similar properties to emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions is that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound. PEG (polyethylene glycol) is often used here. A PLA-PEG diblock compound can be able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or environmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to the food product.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface is coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions on the food product. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsion between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology. Many biological compounds, for instance polysaccharides and proteins, can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging. Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known how these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis could protect against nanoparticles. The outer layer of the skin is called the epidermis, and is divded into many sublayers. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3453 2009-03-31T22:54:13Z

<p>Fredrimu: /* Biopolymer nanofibres */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach $1000,000,000,000 USD by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach $5800000000 by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulation of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk) has postulated, and it is to be found elsewhere, a definition of nanotechnology as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have similar effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters that have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in foods.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingredients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach their destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions have similar properties to emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions is that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound. PEG (polyethylene glycol) is often used here. A PLA-PEG diblock compound can be able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or environmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to the food product.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface is coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions on the food product. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsion between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology. Many biological compounds, for instance polysaccharides and proteins, can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging. Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known what these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis could protect against nanoparticles. The outer layer of the skin is called the epidermis, and is divded into many sublayers. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3452 2009-03-31T22:52:32Z

<p>Fredrimu: /* Biopolymer nanofibres */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach $1000,000,000,000 USD by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach $5800000000 by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulation of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk) has postulated, and it is to be found elsewhere, a definition of nanotechnology as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have similar effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters that have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in foods.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingredients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach their destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions have similar properties to emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions is that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound. PEG (polyethylene glycol) is often used here. A PLA-PEG diblock compound can be able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or environmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to the food product.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface is coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions on the food product. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsikon between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology Many biological compounds, for instance polysaccharides and proteins can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging.Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known what these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis could protect against nanoparticles. The outer layer of the skin is called the epidermis, and is divded into many sublayers. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3451 2009-03-31T22:45:24Z

<p>Fredrimu: /* Nanolaminates */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach $1000,000,000,000 USD by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach $5800000000 by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulation of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk) has postulated, and it is to be found elsewhere, a definition of nanotechnology as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have similar effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters that have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in foods.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingredients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach their destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions have similar properties to emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions is that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound. PEG (polyethylene glycol) is often used here. A PLA-PEG diblock compound can be able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or environmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to the food product.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface is coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions on the food product. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsikon between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology Many biological compounds, for instance polysaccharides and proteins can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging.Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known what these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis could protect against nanoparticles. The outer layer of the skin is called the epidermis, and is divded into many sublayers. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3450 2009-03-31T22:43:53Z

<p>Fredrimu: /* Edible food packaging */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach $1000,000,000,000 USD by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach $5800000000 by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulation of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk) has postulated, and it is to be found elsewhere, a definition of nanotechnology as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have similar effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters that have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in foods.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingredients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach their destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions have similar properties to emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions is that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound. PEG (polyethylene glycol) is often used here. A PLA-PEG diblock compound can be able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or environmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to the food product.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface are coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions of the food. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsikon between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology Many biological compounds, for instance polysaccharides and proteins can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging.Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known what these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis could protect against nanoparticles. The outer layer of the skin is called the epidermis, and is divded into many sublayers. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3449 2009-03-31T22:42:27Z

<p>Fredrimu: /* Biodegredable polymers */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach $1000,000,000,000 USD by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach $5800000000 by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulation of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk) has postulated, and it is to be found elsewhere, a definition of nanotechnology as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have similar effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters that have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in foods.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingredients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach their destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions have similar properties to emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions is that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound. PEG (polyethylene glycol) is often used here. A PLA-PEG diblock compound can be able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or environmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to foods.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface are coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions of the food. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsikon between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology Many biological compounds, for instance polysaccharides and proteins can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging.Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known what these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis could protect against nanoparticles. The outer layer of the skin is called the epidermis, and is divded into many sublayers. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3448 2009-03-31T22:35:41Z

<p>Fredrimu: /* Biopolymeric nanoparticles */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach $1000,000,000,000 USD by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach $5800000000 by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulation of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk) has postulated, and it is to be found elsewhere, a definition of nanotechnology as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have similar effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters that have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in foods.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingredients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach their destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions have similar properties to emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions is that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound. PEG (polyethylene glycol) is often used here. A PLA-PEG diblock compound can be able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or envvironmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to foods.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface are coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions of the food. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsikon between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology Many biological compounds, for instance polysaccharides and proteins can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging.Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known what these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis could protect against nanoparticles. The outer layer of the skin is called the epidermis, and is divded into many sublayers. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3447 2009-03-31T22:29:46Z

<p>Fredrimu: /* Emulsions */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach $1000,000,000,000 USD by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach $5800000000 by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulation of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk) has postulated, and it is to be found elsewhere, a definition of nanotechnology as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have similar effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters that have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in foods.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingredients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach their destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions have similar properties to emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions is that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ it the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound the hydrophobic PLA that can make the PLA-PEG diblock compound able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or envvironmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to foods.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface are coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions of the food. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsikon between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology Many biological compounds, for instance polysaccharides and proteins can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging.Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known what these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis could protect against nanoparticles. The outer layer of the skin is called the epidermis, and is divded into many sublayers. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3446 2009-03-31T22:28:26Z

<p>Fredrimu: /* Emulsions */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach $1000,000,000,000 USD by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach $5800000000 by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulation of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk) has postulated, and it is to be found elsewhere, a definition of nanotechnology as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have similar effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters that have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in foods.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingredients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach their destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions have similar properties to emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions are that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ it the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound the hydrophobic PLA that can make the PLA-PEG diblock compound able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or envvironmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to foods.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface are coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions of the food. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsikon between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology Many biological compounds, for instance polysaccharides and proteins can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging.Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known what these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis could protect against nanoparticles. The outer layer of the skin is called the epidermis, and is divded into many sublayers. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3445 2009-03-31T22:26:41Z

<p>Fredrimu: /* Nano inside - Delivery systems */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach $1000,000,000,000 USD by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach $5800000000 by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulation of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk) has postulated, and it is to be found elsewhere, a definition of nanotechnology as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have similar effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters that have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in foods.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingredients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach their destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions is a class of emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions are that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ it the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound the hydrophobic PLA that can make the PLA-PEG diblock compound able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or envvironmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to foods.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface are coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions of the food. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsikon between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology Many biological compounds, for instance polysaccharides and proteins can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging.Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known what these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis could protect against nanoparticles. The outer layer of the skin is called the epidermis, and is divded into many sublayers. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3444 2009-03-31T22:24:13Z

<p>Fredrimu: /* Regulations */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach $1000,000,000,000 USD by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach $5800000000 by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulation of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk) has postulated, and it is to be found elsewhere, a definition of nanotechnology as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have similar effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters that have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in food.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingrdients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach the destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions is a class of emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions are that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ it the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound the hydrophobic PLA that can make the PLA-PEG diblock compound able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or envvironmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to foods.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface are coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions of the food. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsikon between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology Many biological compounds, for instance polysaccharides and proteins can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging.Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known what these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis could protect against nanoparticles. The outer layer of the skin is called the epidermis, and is divded into many sublayers. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3443 2009-03-31T22:22:11Z

<p>Fredrimu: /* Regulations */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach $1000,000,000,000 USD by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach $5800000000 by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulation of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk)has postulated, and it is to be found elsewhere, a definition as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters which have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in food.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingrdients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach the destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions is a class of emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions are that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ it the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound the hydrophobic PLA that can make the PLA-PEG diblock compound able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or envvironmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to foods.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface are coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions of the food. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsikon between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology Many biological compounds, for instance polysaccharides and proteins can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging.Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known what these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis could protect against nanoparticles. The outer layer of the skin is called the epidermis, and is divded into many sublayers. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3442 2009-03-31T22:21:02Z

<p>Fredrimu: /* Market drivers */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach $1000,000,000,000 USD by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach $5800000000 by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulating of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk)has postulated, and it is to be found elsewhere, a definition as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters which have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in food.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingrdients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach the destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions is a class of emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions are that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ it the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound the hydrophobic PLA that can make the PLA-PEG diblock compound able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or envvironmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to foods.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface are coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions of the food. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsikon between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology Many biological compounds, for instance polysaccharides and proteins can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging.Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known what these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis could protect against nanoparticles. The outer layer of the skin is called the epidermis, and is divded into many sublayers. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3441 2009-03-31T22:19:36Z

<p>Fredrimu: /* Market drivers */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach $1000,000,000,000 USD by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach 5800000000$ by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulating of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk)has postulated, and it is to be found elsewhere, a definition as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters which have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in food.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingrdients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach the destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions is a class of emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions are that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ it the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound the hydrophobic PLA that can make the PLA-PEG diblock compound able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or envvironmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to foods.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface are coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions of the food. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsikon between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology Many biological compounds, for instance polysaccharides and proteins can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging.Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known what these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis could protect against nanoparticles. The outer layer of the skin is called the epidermis, and is divded into many sublayers. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3440 2009-03-31T22:18:23Z

<p>Fredrimu: /* Introduction */</p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in that section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks, presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach 1000 000000000 US $ by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach 5800000000$ by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulating of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk)has postulated, and it is to be found elsewhere, a definition as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters which have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in food.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingrdients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach the destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions is a class of emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions are that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ it the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound the hydrophobic PLA that can make the PLA-PEG diblock compound able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or envvironmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to foods.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface are coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions of the food. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsikon between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology Many biological compounds, for instance polysaccharides and proteins can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging.Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known what these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis could protect against nanoparticles. The outer layer of the skin is called the epidermis, and is divded into many sublayers. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3439 2009-03-31T22:12:33Z

<p>Fredrimu: </p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in this section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks is presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach 1000 000000000 US $ by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach 5800000000$ by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulating of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk)has postulated, and it is to be found elsewhere, a definition as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters which have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in food.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingrdients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach the destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Website: Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt;Website: Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions is a class of emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions are that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ it the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound the hydrophobic PLA that can make the PLA-PEG diblock compound able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or envvironmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to foods.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface are coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions of the food. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsikon between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology Many biological compounds, for instance polysaccharides and proteins can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging.Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known what these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis could protect against nanoparticles. The outer layer of the skin is called the epidermis, and is divded into many sublayers. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3438 2009-03-31T22:11:41Z

<p>Fredrimu: </p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in this section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks is presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach 1000 000000000 US $ by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach 5800000000$ by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulating of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk)has postulated, and it is to be found elsewhere, a definition as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters which have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in food.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingrdients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach the destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt; &quot;emulsion.&quot; Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions is a class of emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions are that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Website: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ it the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound the hydrophobic PLA that can make the PLA-PEG diblock compound able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Website: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or envvironmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to foods.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface are coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions of the food. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Website: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsikon between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology Many biological compounds, for instance polysaccharides and proteins can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging.Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known what these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis could protect against nanoparticles. The outer layer of the skin is called the epidermis, and is divded into many sublayers. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Website: http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

Fredrimu http://nanowiki.no/index.php?title=Applications_of_nanotechnology_for_the_food_sector&diff=3266 2009-03-27T16:01:35Z

<p>Fredrimu: </p> <hr /> <div>STILL UNDER CONSTRUCTION --fredrik and reidun<br /> <br /> ==Introduction==<br /> [[Image:lab.jpg|right|thumb|400px|]]<br /> Nanotechnology has opened new avenues in the research and development of food technology. It is being used as a means to understand how physiochemical characteristics of nano-sized substances can change the structure, texture and quality of food. Application of this area already span development of improved tastes, color, flavor and consistency of foodstuffs, increased absorbtion of nutritions and health supplements, new food packaging with improved barrier, mechanical or antimicrobial properties, and nanosensors for traceability and monitoring the conditions of food during transport and storage&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;.<br /> The rapid profilation of nanotechnologies in a wide range of consumer products raises a number of safety, environmental, ethical and regulatory issues. <br /> <br /> Even though the research of applications of nanotechnology in foods is going on strongly, there are currently very few products available. According to the Woodrow Wilson database called &quot;The Project on Emerging Nanotechnologies&quot; there are currently only three available products using nanotechnology.&lt;ref name=&quot;wilson&quot;&gt;Website: &quot;The Project on Emerging Nanotechnologies&quot; (http://www.nanotechproject.org/about/mission/) Visited 2009.03.21&lt;/ref&gt;<br /> <br /> This text presents an overview of current trends in research on nanotechnology in food sector. The text consists of four large sections: market drivers, nano inside, nano outside and health risks. Market drivers present a quick overview of the economic background of nanotechnology in food today. Nano inside concerns the application of nanotechnology inside the food products. The focus in this section is delivery systems, how functional ingredients are delivered, and not so much how the delivered particles react when they arrive, since the latter field is still relatively unknown (also mentioned under the health risks section). Nano outside presents how different technologies can be used to make food packaging. The last section, health risks is presents research on the health risks concerning the applications of these new technologies.<br /> <br /> ==Market drivers==<br /> Nanotechnology has in recent years developed into a wide-ranging global industry. The global marked of nanotechnology is widely expected to reach 1000 000000000 US $ by 2015 with approximately two million workers&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. Concerning the food sector, estimates of current global marked size are varied. Furthermore, a lot of the information available is aimed at projecting the &quot;magical potential&quot; of nanotechnology when applied to food, rather than real products and applications that are available in a few years time. A report from the consulting firm Cientifica estimates that the overall market value of food applications of nanotechnology will reach 5800000000$ by 2012 (food processing $1303 millions, food ingredents $1475 millions, food safety $97 millions and food packaging $2930 millions). <br /> <br /> <br /> A number of major food and beverage companies are reported to have an interest in nanotechnology. These include Nestlé, Kraft and Heinz. The food industry is ultimately driven by profitability, which is consequent on gaining consumer acceptance. This industry is constantly looking out for new technology to improve the nutritotional value, shelf life, taste and quality of their food in addition to new and innovative products. Nanotechnology processes and materials can provide answers to many of these needs, as it offers the ability to control and manipulate properties of substances close to molecular level.<br /> <br /> === The public acceptance of nanotechnology in foods ===<br /> <br /> The introduction of new technology can be met with public skepticism. It remains unclear how public attitudes will impact the future of nanotechnology in the food sector. However, it is well known that lack of knowledge of potential risks or lack of communication of risks and benefits can raise concerns amongst the public. A recent example is the negative reaction from the EU-consumers to genetically modified (GM) food. In a study taken place in Switzerland a random selected group (337 people) were given a mail survey to answer about the application of nanotechnology in food and food packaging. The survey indicated that people were less sceptic about nanotechnology food packaging than nanotechnology foods.&lt;ref name=&quot;perceived_risks&quot;&gt;Siegrist M, Stampfli N, Kastenholz H, Keller C, &quot;Perceived risks and perceived benefits of different nanotechonology foods and nanotechnology food packaging&quot;, Appetite (2008); 51: 283-290.&lt;/ref&gt;<br /> <br /> === Regulations ===<br /> <br /> Questions have been raised regarding the regulating of new products on the marked. It is unclear whether the current regulations will be able to handle new properties with where materials used before can have new properties. And, if not, what information is aditionally required. From a number of reports it becomes clear that there is no nano-specific regulation in the EU or other countries (in 2007). It as been made clear that companies making new products containing nanotechnology will have to obey current rules, and the Health Council of the Netherlands have considered that the best thing to do would be to modify allready existing rules to fit the new technology. However, such modifications can not be made with out the proper competance. As a start there is need for a strict definition of nanotechnology. SCNIHR (Scientific Committee on Emerging and Newly Identified Health Risk)has postulated, and it is to be found elsewhere, a definition as &quot;the order of 100nm of less&quot;. The problem is that, depenting of other factors, different particles with dimensions higher than 100nm also can have effects because of their small size. Where characterization of chemicals normally is easily done (for instance by measuring purity and concentration), physio-chemical characterization of nanoparticles is difficult because of more compelx technical methods and because the lack of knowledge of which parameters which have to be measured. There is especially lack of methods for in situ observations and detection of delivery systems.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==Nano inside - Delivery systems ==<br /> <br /> &quot;Nano inside&quot; is used as a term for applied nanotechnology in the ingredients in food.&lt;ref name=&quot;perceived risks&quot;/&gt; This can either be applied as existing ingredients beeing made into particles in nano scale (1-100nm) which would give the material used new properties, or developing new types of ingrdients. These ingredients could for instance give the food higher nutritional values and increased shelf life. As mentioned in the introduction, and also in the health risk section, the current research mainly concerns how the functional ingredients reach the destination. This is called a delivery system. The delivery system makes sure that the functional ingredient reaches its destination, that the functional ingredient is not degraded during the transport and that the release of the functional ingredient is done properly. Factors affecting the release rate can for example be pH, ionic strength or temperature. It is also important that the delivery system is compatible with other components in the system.&lt;ref name=&quot;weiss&quot;&gt;Weiss J, Takhistov P, McClements DJ, &quot;Functional Materials in Food Nanotechnology&quot;, Journal of Food Science (2006); 71(9): 107-116. &lt;/ref&gt;. While most reports published today mainly concerns the future possibilties of the techniques used, there are currently few commercial available products using these application methods listed under. One exception though is a type of bread called Tip Top Up from the Australian company Tip Top. Using nanoencapsulation, tuna fish oil is used for getting Omega 3 acids into the bread. The nanosize particles are not detected by the taste buds and therefore the bread will have no taste of fish oil.&lt;ref name=&quot;tiptop&quot;&gt;Tip-Top (http://www.tiptop.com.au/), visited 2009.03.21&lt;/ref&gt;&lt;ref name=&quot;chaudry&quot;/&gt;<br /> <br /> <br /> ====Emulsions====<br /> [[Bilde:Emulsion.gif|right|thumb|200px|An oil-in-water (O/W) emulsion&lt;ref name=&quot;emulsion&gt;Website: http://www.ifr.ac.uk/Materials/fractures/emulsions.html Visited: 2009.03.22&lt;/ref&gt;]]The delivery of nano particles applied in food technology is very often in form of emulsions (nanoemulsions)&lt;ref name=&quot;health&quot;&gt;Bouwmeester H, Dekkers S, Noordam MY, Hagens WI, Bulder A, Heer C, ten Voorde SECG, Wijnhoven S, Marvin HJP, Sips AJAM, &quot;Review of health safety aspects of nanotechnologies in food production&quot;, (2009), Regulatory Toxicology and Pharmacology 53 (2009); 52–62&lt;/ref&gt;An emulsion is a mixture of two or more liquids where one is distributed as droplets in the other liquid. &lt;ref name=&quot;emulsion&quot;&gt; &quot;emulsion.&quot; Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 14. Mar. 2009 (http://www.britannica.com/EBchecked/topic/186307/emulsion)&lt;/ref&gt; One should notice that nano-emulsions is a class of emulsions (unlike microemulsions which have different thermodynamic properties than emulsions). Nano-emulsions have a droplet size of 20nm to 500nm. The formation is not spontaneous and their properties do not only depend on thermodynamic conditions, but also the way they are prepared.&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt; [[Bilde:multilayeremulsion.jpg|right|thumb|350px|Illustration of fabrication of multilayer emulsion&lt;ref name=&quot;weiss&quot;/&gt;]]Encapsulating functional components in the droplets and modication of the interfacial layer between the droplet and the continuous have been shown to have a slowdown of the chemical degradation process.&lt;ref name=&quot;weiss&quot;/&gt; Multiple emulsions, emulsions containing several layers can also be used (for instance a oil-in-water-in-oil emulsion (O/W/O). The advantage using the multiple emulsions are that phase components that are soluble in the same type of phase can be separated and still contained in the same colloidal particle. Multilayer emulsions, emulsion containg only one phase but has a multilayer interface has also been researched. Emulsions with oil droplets surrounded by multilayer interfaces have been shown to have better stability against enviromental stress than single layer emulsions. The multiple layers can be made by electrostatic deposition in which polyelectrolytes are adsorbed on surfaces of oppositely charged colloidal particles. &lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;porrasa&quot;&gt;M. Porrasa, C. Solansb, C. Gonzáleza, A. Martíneza, A. Guinarta and J.M. Gutiérre, &quot;Studies of formation of W/O nano-emulsions&quot;, Colloids and Surfaces A: Physicochemical and Engineering Aspects (2004); 115-118&lt;/ref&gt;<br /> <br /> ====Association colloids====<br /> <br /> [[Bilde:Micelle.PNG|left|thumb|200px|A micelle&lt;ref name=&quot;micelle&quot;&gt; Wikipedia: http://en.wikipedia.org/wiki/Micelle Visited: 2009.03.22&lt;/ref&gt;]]Association colloids are aggregation of surface-active molecules. Examples of association colloids include microemulsions, micelles, vesicles, bilayers, reverse micelles and liquid crystals. They can be used for delivering polar, non-polar and amfiphiphilic functional ingredients. Advantages of association colloids are that they are thermodynamic favorable (reaction resulting in negative Gibbs' energy) and often form transparent solutions. The disadvantages are that a high concentration of surfactants is needed to form the association colloids and that they may dissociate if the solution is diluted.&lt;ref name=&quot;weiss&quot;/&gt;&lt;ref name=&quot;kolloidboka&quot;&gt;Hiemenz PC, Rajagopalan R, &quot;Principles of Colloid and Surface Chemistry&quot;, Taylor &amp; Francis Group (1997)&lt;/ref&gt; Micelles are clusters of amphipathic molecules which are aggregating together. Considering a micelle in a polar solvent, the core of the micelle consists of the hydrophobic end (predominantly hydrocarbon)while the polar heads will point outwards to the water. The radius core of the micelle, available for functional ingredients, roughly equals the length of the fully extended hydrocarbon tail. A typical micelle will thus have a radius on a couple of nanometers. When the concentration of surfactants in the solution reach the critical micelle concentration, insoluble particles can interact with the nonpolar heads of the surfactants and become encapsulated in the micelle. Reversed micelles will occur when surfactants are added to a non-polar solvent. The polar head groups will then point inwards.&lt;ref name=&quot;kolloidboka&quot;/&gt;<br /> <br /> ====Biopolymeric nanoparticles====<br /> <br /> Biopolymeric nanoparticles are made of one or several biodegradable polymers. PLA (polylactic acid) is a main component of many biopolymeric nanoparticles. PLA is already widely used in for instance biomedicine because it is biodegradable and can be used for surgery (for instance as sutures). The biodegradable property of PLA can be both an advantage and disadvantage. It will degrade quickly in the bloodstream and therefore it can be suitable for delivering functional ingredients there, but if the ingredient is supposed to be carried to another internal organ it the encapsulation will most likely degrade. PLA also degrades in intestinal fluid, but this can be overcome by adding a a hydrophilic compound the hydrophobic PLA that can make the PLA-PEG diblock compound able to form a micellar structure and entrap the compound that is to be delivered. PLA and PLA-PEG nanoparticles have very good encapsulation properties, but the main reason for using these particles for a delivery system is that they are non-toxic. PLA-PEG-particles will have a lower zeta potential (a lower surface charge) than PLA-particles, and this will influence the interaction of the particles with other compounds in the food.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ==Nano outside - functional food packaging==<br /> <br /> Nanotechnology derived food packaging materials is the largest category of current nanotechnology applications for the food sector. Food packaging materials with improved mechanical, barrier and antimicrobial properties are of interest, and also nano-sensors for traceability and monitoring of conditions of food during transport and storage. Packaging materials for foodstuff, like any other short-term storage packaging material, represent a serious global environmental problem. A big effort to extend the shelf-life and enchange food quality while reducing packaging waste has encouraged the exploration of new, nanotechnology-based materials.<br /> <br /> <br /> ===Nanocomposites for food packaging===<br /> Polymer composites are mixtures of polymers with inorganic or organic additives. Appropriately adding nanoparticles to a polymer matrix can enhance its performance, often in very dramatic degree, by simply capitalizing on the nature and properties of the nanoscale filler. With nanotechnology fillers, the composites can exhibit significant improvement in modulus, dimensional stability and resistance to humidity or gas.&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt; Other advantages include low density, transparency, better surface properties, fire resistance and recyclability. Due to very large aspect ratios, a relatively low concentrations of nanoparticles is sufficient to change the properties of a material. These benefits have led to the development of a variety of nanoreinforced polymers, commonly referred to “nanocomposites”, which typically contains up to 5% nanoparticles.&lt;ref name=&quot;chaudry&quot;&gt; Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;<br /> <br /> [[Image:claycomp.jpg|left|thumb|400px|'''Nanocomposites:''' Schematic drawing of exfoliation and intercaltion states. &lt;ref name=&quot;nanocomposites&quot;&gt;Website: http://imi.cnrc-nrc.gc.ca/Carrefour_d_informations/Factsheets/pnc_tech_e.html Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with nanoclay====<br /> The polymer composites incorporating clay nanoparticles are among the first nanocomposites to emerge on the market as improved materials for food packaging. The nanoclay mineral used in these materials, montimorillonite, is a widely available natural clay derived from volcanic ash and rocks&lt;ref name=&quot;chaudry&quot;&gt;Chaudry, Scotter, Blackburn, Ross, Boxall, Castle, Aitken &amp; Watkins, &quot;Applications and implicatons of nanotechnologies for the food sector&quot;, Food Additives and Contaminants, March 2008&lt;/ref&gt;. The clay has a unique morphology that contains one dimension on the nanoscale. Nanoclay-composites have been developed for potential use in a variety of food packaging applications and some products are already available for the consumer. The montmorillonite is hydrated alumina-silicatelayered clay. This special clay has a structure that limits the permeation of gas due to the large aspect ratio and tutourity &lt;ref name=&quot;applications&quot;&gt; Sozer &amp; Kokini, Nanotechnology and its applications in the food sector, Trends in Biotechnology Vol.27 No.2 &lt;/ref&gt;. To obtain the polymer composite improvements mentioned above, a small percentage of clay can be included in the polymer matrix. This process is called solid layer dispersion in polymer and involves two major steps; intercalation and exfoliation&lt;ref name=&quot;sorrentino&quot;&gt; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Foof Science and Technology 18, 2007 &lt;/ref&gt;. In the intercalation step, the d-spacing in the crystal structure increases from its intrinsic value, as polymer chains or monomer molecules diffuse into the clay gallaries. In an intercalated state, the inorganic layers remain parallel to each other. In exfoliation, the clay particles are released from this system and are dispersed in the matrix polymer with no apparent particle interactions. The result is layers of nanoclay woven into the polymers structural matrix. Introduction of the dispersed clay layers into the polymer matrix structure has been shown to greatly improve the overall mechanical strength and barrier properties of the material, making the use of nanocomposites films industrially practicable&lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. The known industrial applications of nanoclay in multilayer film packaging include beer bottles and thermoformed containers. Miller Brewing Co. (USA) and Hite Brewery Co. (South Korea) have reported to be using this technology in their beer bottles.<br /> <br /> <br /> [[Image:nurser.jpg|right|thumb|300px|'''Baby Dream:''' &quot;Nano Silver Baby Milk Bottle&quot; from Baby Dream Co. Ltd. South Korea. &lt;ref name=&quot;babybottle&quot;&gt;Website: http://babydream.en.ec21.com/product_detail.jsp?group_id=GC00887651&amp;product_id=CA00895940&amp;product_nm=Nurser Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> ====Composites with metalparticles====<br /> Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed for packaging because of their antimicrobial or for example UV-resistant properties. Based on the antimicrobial action of nanosilver, a number of &quot;active&quot; food packaging materials has been claimed to inhibiting the growth of microorganisms. Examples from the internet include &quot;Nano Silver Food Containers&quot; form A-DO Korea, and &quot;Nano Silver Baby Dream Co. Ltd. from South Korea. Silver has been used in medical care for ages because of its antimicrobial properties. Silvernanoparticles are currently being used in a wide range of consumer products including antibacterial refrigerators and socks. When in contact with bacteria and fungus the silver nano particles will adversely affect cellular metabolism and inhibit cell growth. The silver suppresses respiration and transport of substrate in the microbial cell membrane due to the chemical properties of its ionized form, Ag+. Ag+ forms strong molecular bonds with substances used by bacteria, such as molecules containing sulfur, nitrogen, and oxygen. Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.<br /> <br /> ====Chitosan====<br /> [[Image:Chitosan_Haworth.jpg|left|thumb|200px|'''Chitosan:''' Haworth projection of chitosan&lt;ref name=&quot;chitosan&quot;&gt; Wikipedia: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;.]]<br /> Nanocomposites have also been developed using for example chitosan. Chemically derived by deacetylation of chitin, an abundant polysaccharide found in shellfish, chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It has a number of commercial and possible biomedical uses&lt;ref name=&quot;chitosan&quot;&gt; Wikipedia: Chitosan (http://en.wikipedia.org/wiki/Chitosan)Visited 22.03.2009 &lt;/ref&gt;. Chitosan possesses a unique cationic nature relative to other neutral or negatively charged polysaccharides. In an acid environment, the amino group NH2 in chitosan can be protonated to NH3 +, which yields antifungal or antimicrobial activities since cations can bind to anionic sites on bacterial and fungal cell wall surfaces. Further, chitosan is a nontoxic natural polysaccharide and is compatible with living tissue.<br /> These appealing features make chitosan widely applicable in wound healing, production of artificial skin, food preservation, and cosmetics.<br /> <br /> ====Biodegredable polymers====<br /> New research on nanocomposites based on biodegredable polymers is increasing. Biodegradable plastics are polymeric materials of which at least one step in the degradation process is through metabolism in the presence of natural occurring organisms. Biodegradation leads to fragmentation or disintegration of the plastic with no toxic or envvironmentally harmful residue &lt;ref name=&quot;sorrentino&quot;&gt; &quot;sorrentino.&quot; Sorrentino, Gorrasi &amp; Vittora, &quot;Potential perpectives of bio-nanocomposites for food packaging applications, Trends in Food Science and Technology 18, 2007 &lt;/ref&gt;. However, current biodegradable films exhibit<br /> poor barrier and mechanical properties and these properties need to be improved considerably before they could replace traditional plastics [23,24] and thus help to manage the world’s waste problem. Introduction of nanoparticles as described above can dramatically improve the properties of biodegredable polymers &lt;ref name=&quot;applications&quot;/&gt;.<br /> <br /> ===Edible food packaging===<br /> Bio-based packaging materials, such as edible and biodegradable films from renewable resources are interesting because they could, at least to some extent, solve the waste problem. Edible films and coatings are defined as thin, continous layers of edible material used as coating or as a film placed on food components. The difference between a coating and a film is that a coating is an integral part of the food product formed directly on it by spaying, dipping etc, while a film is in contrast a freestanding structure formed and then applied to foods.&lt;ref name=&quot;Balasubramaniam&quot;&gt;Balasubramaniam, Chinnan, Mallikarjunan &amp; Phillips, 1997; Guilbert et al., 1997 &lt;/ref&gt;.<br /> <br /> ====Nanolaminates====<br /> Films and coatings can be manufactured in many ways. One option is to use nanolaminates. A nanolaminate consists of two or more chemically bonded layers of polymers. The LbL-technology provides a way to create the nanolaminates. In this process a charged surface are coated with interfacial films consisting of nanolayers of different materials. The electrostatic forces hold these layers together. Very thin films (1-100nm) can be created with this technology. These films can give many properties to the food applied on. This can be shelf-life improving properties, for instance that it can prevent moisture from escaping. The films can also serve as encapsulation of functional ingredients, giving flavour, vitamins etc to the food. Because nanolaminates are very thin they are more often used as coatings than as films. Application of nanolaminate coating can be done by dipping the food into several solutions where substances will be attracted to the surface most often by electrostatic forces. Another way of coating the food is to spray the different solutions of the food. Examples of substances that can be used for creating the laminates are proteins, polysaccharides (natural polyelectrolytes), charged lipids (phospholipids, surfactants) and colloidal particles. [[Image:Laminates2.JPG|right|thumb|200px|Illustration of a laminate formed from a protein and a polysaccharide&lt;ref name=&quot;weiss&quot;/&gt;]]<br /> <br /> Changing the properties of the applied layer can be done in several ways.<br /> <br /> * Changing the type of substances in the solution.<br /> * Changing enviromental parameters in the solution used.<br /> * Changing number of dipping steps.<br /> * Changing the order of the dipping steps.<br /> <br /> There are still many uncertainties for this technique. For instance the influence of the topography of the surface on the effect of the coating has still not been properly established.&lt;ref name=&quot;weiss&quot;/&gt;<br /> <br /> ====Biopolymer nanofibres====<br /> <br /> In addition to manufacturing nanoparticles the new option of electrospinning of materials allows fibres of biopolymers to be made in addition to the nanoparticles refered to earlier. These fibres can be used both as food packaging and as encapsulation of functional ingredients in the material. Electrospinning is a technique which has been applied to synthetic polymers for a while, but as the technology gets better it is also possible to electrospin biopolymers. What makes electrospinning of biopolymers difficult is that they in general can not handle as much mechanical stress as synthetic polymers. [[Image:Electrospinning_setup.png|right|thumb|300px|Schematic image showing a setup for electrospinning &lt;ref name=&quot;electrospinning&quot;&gt;Wikipedia: Electrospinning (http://en.wikipedia.org/wiki/Electrospinning) Visited: 2009.03.22&lt;/ref&gt;]]<br /> <br /> The principle of electrospinning is based on deposition of of a solution containing the polymer on a stationary plate or a rotating drum or disk. The solution (often organic) containing the polymer is put into a syringe with a thin metallic capillary needle at the end. At the end of the needle, ordinarily, a droplet would form, balancing the surface tension and the gravitational forces. Applying an electrical field will make a more complex situation causing charge repulsikon between the polymer and the solvent molecules and there will be an attraction to the target electrode. A cone shape structure is formed (Taylor cone) pointing towards the grounded deposition plate (or drum/disk). At a critical point a thin jet of the solution would burst from the tip of the Taylor cone and this jet will be accelerated towards the grounded plate (or drum/disk). In this process the solvent can evaporate causing only the polymer to be deposited. Also differences in charge on the surface of the jet may cause it to bend. <br /> <br /> Research has been done and is still going on in the field of using this technology Many biological compounds, for instance polysaccharides and proteins can be suitable for electrospinning, making very interesting possibilities for delivery systems and food packaging.Even though there are very interesting possibilities in this technology and research going on, there are currently very few applications of this in the food sector.&lt;ref name=&quot;kriegel&quot;&gt;Kriegel C, Arrechi A, Kit K, McClements DJ, Weiss J, &quot;Fabrication, Functionalization, and Application of Electrospun Biopolymer Nanofibers&quot;, Critical Reviews in Food Science and Nutrition, 48:775–797 (2008)&lt;/ref&gt;<br /> <br /> == Health risks ==<br /> It is known that materials at nano-scale exhibit different properties than found at macro-scale. An extreme example concerning different properties at different scales is aluminum oxide. Aluminum oxide is used in dentistry because it is inert at macro-scale, but when manufactured as nano-scale particles it can spontaneously explode and has been tested as a potential rocket fuel. Examining new nano-materials properties as particle size, mass, chemical composition, aggregation, and surface charge of the nanoparticles must be done. There are currently available data that indicates that properties of nanoparticles, such as surface charge and functional groups can influence absorption, metabolism, distribution and excretion. Still, very little is known what these physio-chemical properties will affect the behavior of the particles in the body. It is three possible ways a nanoparticle, or any particle, could enter the human body. That is through the skin, through inhalation or through ingestion.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Entrance of nanoparticles===<br /> ====Dermal exposure====<br /> Nanoparticles can have an impact if they penetrate the outer layers of the skin. Some studies show that a healthy epidermis could protect against nanoparticles. The outer layer of the skin is called the epidermis, and is divded into many sublayers. There are findings that fluorecent microspheres or dextran beads (&gt;1&lt;math&gt;\mu&lt;/math&gt;m) can, when in motion, penetrate the stratum corneum (the uppermost sublayer of the epidermis), go down in the epidermis and occasionally reach the dermis. If nanoparticles penetrate the dermis they could translocate via lymph to regional lymph nodes. Some researches claim that small titanium dioxide particles (about 20nm) could even interact with the immune system when they penetrate the skin. It should of course be noticed that possible health consequences still remain rather speculative.&lt;ref name=&quot;chi-fai_chau&quot;&gt; Chau C, Wu S, Yen G, &quot;The development of regulations for food nanotechnology&quot;, Trends in Food Science &amp; Technology (2007) 18: 269-270 &lt;/ref&gt;<br /> <br /> ====Inhalation====<br /> If a particle has a aerodynamic diameter less than 10&lt;math&gt;\mu&lt;/math&gt;m it can pass through the nasal cavity to the lungs. The aerodynamic diameter describes the particles aerodynamical behaviour as if it was a perfect sphere with density 1.&lt;ref name=&quot;aero&quot;&gt;Aerodynamic diameter, http://en.wikipedia.org/wiki/Aerodynamic_diameter, visited 2009.03.17&lt;/ref&gt; Studies indicate that nanoparticles, because of their size, are more toxic than larger particles of the same material. The particles can get deep into the lungs, and when inhaled, some nanopartciles may accumulate in the lungs and cause cronic diseases such as pulmonary (lung) inflammation. There are also speculations if the particles when in the blood stream, would be able to cross the blood brain barrier. However, it is also here hard to draw conclusions and individual nanomaterials needs to be evaluated.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;<br /> ====Ingestion====<br /> Nanoparticles can avoid intestinal clearance mechanisms and penetrate deeply into tissues and fine capillaries. It seems that small particles can penetrate the mucus layer faster than larger particles. In the mucus layer, it also seems that the diffusion is dependent of the charge of the particles. Anions can reach the epithelial surface under the mucus layer, while cations stays trapped in the mucus. The gastrointestinal epithelium is the second barrier the particles reach and it is a tissue of cells that line cavities and surfaces of structures.&lt;ref name=&quot;epithelium&quot;&gt;Website: http://en.wikipedia.org/wiki/Epithelium visited 2009.03.23&lt;/ref&gt; The cells in the gastrointestinal epithelium are connected with tight junctions and as bacterias, toxins and immunogens can enter here it is to be considered a risk that nanoparticles can enter through this way. In addition to those particles directly ingested, particles inhaled and cleared by the mucociliary apparatus can end up in the gastrointestional tract.&lt;ref name=&quot;chi-fai_chau&quot;/&gt;&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ===Distribution of entered nanoparticles===<br /> Even though little is known about the nutrional effect of having functional ingredients as nanoparticles there have been done some research on the distribution of nanoparticles in the human body.<br /> <br /> There are tests indicating that nanoparticles will have a widespread distribution inside an animal body, where the smallest particles even can raech the brain and bone marrow. Also in a cellular level there are indications that cell membranes can be penetrated by nanoparticles. Gold and titanium-oxide nanoparticles have been identified inside human red blood cells. The blood-brain barrier restricts permeability to the molecules which are lipophilic, actively transported or small soluble, but there exist eveidence that some nanoparticles can cross this barrier.&lt;ref name=&quot;health&quot;/&gt;<br /> <br /> ==References==<br /> <br /> &lt;references/&gt;</div>

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