外文翻譯--離子液體對(duì)膠原纖維的溶解和再生（英文）

1、InternationalJournalofBiologicalMacromolecules51 (2012) 440–448ContentslistsavailableatSciVerseScienceDirectInternationalJournalofBiologicalMacromoleculesjournalhomepage:www.elsevier.com/locate/ijbiomacDissolutionandrege

2、nerationofcollagenfibersusingionicliquidZhuojunMeng a, XuejingZheng a,?, KeyongTang a, JieLiu a, ZhiMa a, QiaolingZhao ba CollegeofMaterialsScienceandEngineering,ZhengzhouUniversity,Henan450052,Chinab ShanghaiInstituteo

3、fOrganicChemistry,ChineseAcademyofSciences,Shanghai200032,Chinaarti c l e i nf oArticlehistory:Received3February2012Receivedinrevisedform27May2012Accepted29May2012Available online 4 June 2012Keywords:CollagenDisso

4、lutionRegenerationIonicliquidabstra c tNativeskin collagenfibers weresuccessfullydissolvedin the ionicliquid, 1-butyl-3-methylimidazoliumchloride([BMIM]Cl),and regeneratedin differentprecipitators.Theobservation

5、by polarizedopti-calmicroscopyshowedthat the crystalstructureofcollagenfibers had been destroyedby[BMIM]Clduringthe heating.Temperature-dependentFTIR was appliedto detect the structuralchangeof colla-gen/[BMIM

6、]Clduring dissolving.Thestructureofregeneratedcollagenwas characterizedby FTIRandXRD.It showedthat the triple helicalstructureof collagenhad been partlydestroyedduring the dis-solutionand regeneration.The fil

7、m formingabilityand the thermostabilityof the regeneratedcollagenwashighlydependenton the precipitatingtreatment.Thepossiblemechanismsof dissolvingof collagenin[BMIM]Cland the regenerationin the precipitator

8、shave been proposed.Thecollagen/cellulosecom-positewith differentforms (film, fiber, gel) can be successfullypreparedby using[BMIM]Clas medium.© 2012 Elsevier B.V. All rights reserved.1.IntroductionCollag

9、en,afibrousstructuralproteinwithexcellentmechanicalproperties,isoneofthemostabundantproteinsinnature[1–3].Itisfoundexclusivelyinanimals,especiallyinthefleshandbio-logicaltissuesofmammals,includingbone,tendon,teeth,skin,l

10、igamentandcartilage,makingupabout25–35%ofthewhole-bodyprotein[4–7].Thisfibrous,structuralproteincomprisesaright-handedbundleofthreeparallel,left-handedhelices[8]. Becauseofitsgoodbiocompatibilityandbiodegradability,colla

11、genhasmanyapplicationsinthecommercialfieldsoffood[9], cosmetic[10]andmedicaluses[11–14]. However,duetothestronginter-andintra-molecularhydrogenbonds,ionicbonds,vanderWaals’forceandhydrophobicbondsbetweenthepolarandnon-p

12、olargroups,itisextremelydifficulttodissolvecollagen,whichtremendouslylimittheapplicationofcollageninmanyfields.Ionicliquids(ILs),agroupofsaltsthatexistinliquidsstateatrelativelylowtemperatures[15],beingconsideredasdesira

13、blegreensolvents[16],havebeendevelopedasanewclassofsolventformanynaturalpolymers[17].ILshavemanyattractiveproper-ties,suchasnegligiblevaporpressures,enhancedreactionrates,improvedselectivityandyields,andcanberecoveredaft

14、erthepro-cess.Swatloskietal.[18]firstusedILsascellulosesolvents,andreportedthat1-butyl-3-methylimidazoliumchloride([BMIM]Cl)? Correspondingauthor.Tel.:+8637167763216;fax:+8637167780050.E-mailaddress:xuejing.zheng@gmail.c

15、om(X.Zheng).couldbeutilizedtodissolvecellulose.Thehighchlorideconcen-trationandactivityin[BMIM]Clishighlyeffectiveinbreakingthehydrogenbondingnetworkofthecellulose.Wu etal.[19]foundthat1-allyl-3-methylimidazolechloride([

16、AMIM]Cl)wasanovelILwithgoodpropertiesforcellulosedissolution.Phillipsetal.[20]usedILs([BMIM]Cl,[BMIM]Br,[BMIM]I,and[BMIM]BF4)todissolveandregeneratesilkworm(Bombyxmori)silk.Theyalsosuccessfullyregeneratedsilkfibroinbywet

17、spinningfrom1-ethyl-3-methylimidazoliumchloride(EMIM]Cl)solventsystem[21].Xieetal.[22]reportedthat[BMIM]Clwasanexcellentsolventforwoolkeratin.Thethermalstabilityoftheregeneratedwoolker-atinwasslightlysuperiortothatofnatu

18、ralwoolkeratinfibers.Recently,Wangetal.[23]usedILstodissolvechitin.TheyreportedthatthedissolutionbehaviorofchitininILswasaffectedbythedegreeofacetylation,thecrystallinity,andthemolecularweightsofchitin,aswellasthenatureo

19、ftheanionoftheionicliq-uid.We foundthattheILcandestroythestructureofcollagenfibersandmakesitanattractivesolventforinsolublecollagenfibers[24].Thepresentworkdiscussesthedissolutionofnativeskincollagenfibersbyusing1-butyl

20、-3-methylimidazoliumchloride([BMIM]Cl)andutilizingdifferentprecipitantstoregeneratecol-lagenfilmsfromthecollagen/ILsolution.Collagenutilizedinthisworkwascommercialskincollagenfiberswithoutanypretreat-ment.Thedissolvingpr

21、ocesseswererecordedbyusingpolarizedopticalmicrocopy(POM).Thepossibledissolutionandregenera-tionmechanismswereproposed.ThestructureandpropertiesofregeneratedcollagenfilmswereanalyzedbyusingFTIR,XRDand0141-8130/$–seefrontm

22、atter ©2012 Elsevier B.V. All rights reserved.http://dx.doi.org/10.1016/j.ijbiomac.2012.05.030442 Z.Mengetal./ InternationalJournalofBiologicalMacromolecules51 (2012) 440–448Fig.2.Polarizedopticalmicroscopyphotosoft

23、hedissolvingprocessofskincollagenfiberin[BMIM]Clatdifferenttemperatures(a)roomtemperature25 ?C,(b)80 ?C,(c)90 ?C,(d)100 ?C,(e)110 ?C,(f)120 ?C.3.3.ThemorphologyofregeneratedcollagenfilmsCollagenwastriedtobeprecipitatedfo

24、rmtheILsolutionbytheadditionofwater,orotherprecipitatingsolventsincludingethanol,acetoneandmethanol.Collagencouldberegeneratedintodifferentforms.Byextrusionofthecollagen/ILsolutionintoprecipitator,thinfibersandrodswerepr

25、epared.Bycastingthecollagen/ILsolutiononaPTFEplateandthensoakingtheplateintotheprecipitator,thinfilmswereprepared.Fig.3showsthephotosofflocculousnativecollagenfibersandtheregeneratedcollagenfilms.Theregener-atedfilmswith

26、deionizedwater(Fig.3b)andethanol(Fig.3c)showsmoothandcompactsurfaces.Thefilmregeneratedwithacetone(Fig.3d)andmethanol(Fig.3e)presentsaroughandporoussur-face.Itisseenthatregeneratedcollagenwithbetterfilmformingabilitycanb

27、eobtainedwithdeionizedwaterandethanol.SEMimagesofthesurfacemorphologyofnativecollagenfibersandtheregeneratedcollagenfilmsareshowninFig.4.Thenativeskincollagenfibers(Fig.4a)havewidthofabout40–50?mandlengthfromhundredsofmi

28、cronstomillimeters.Whencolla-gen/[BMIM]Clwasimmersedinprecipitators,regeneratedfilmswithdifferentmorphologycanbegot.Thefilmregeneratedinion-izedwaterhassmoothmorphology(Fig.4b).Thefilmsoakedinethanol(Fig.4c)isrougherbuts

29、tillcontinuous.However,therearecertainholesinthefilmspreparedinacetone(Fig.4d)andmethanol(Fig.4e).Itisseenthatthemorphologyofregeneratedfilmscanbeverydifferentbyusingdifferentprecipitators.3.4.Possibledissolutionandregen

30、erationmechanismsofcollagenfibersinionicliquidItisknownthatcollagenhastherepetitivesequenceGly-X-Y,whereXandYrepresentaminoacidsotherthanglycine.ProlineiscommonlyfoundintheXpositionand4-hydroxyprolineintheYpositionoftheG

31、ly-X-Ytriplets.Thetertiarystructureofcollagenconsistsofthreeleft-handedhelicestwistedintoaright-handedhelix.Thestructureofthetriplehelicesofcollagenisstabilizedbythepresenceofthestronginter-andintra-molecularhydrogenbond

32、s,ionicbonds,vanderWaals’forceandhydrophobicbondsbetweenthepolarandnon-polargroups.Fig.5showstheproposeddissolutionmechanismofcollagenin[BMIM]Cl.ItisdeducedthatILcandissolvethecollagenfibersbymainlybreakingthehydrogenbon

33、dsandtheionicbondsincollagenmacromolecules.Itisspec-ulatedthatoxygenandhydrogenatomsofthecollageninteractwithionicliquids.TheCl? ionsassociatedwiththeaminohydroxylofcollagenand[BMIM]+ complexeswiththecollagenesteroxy-gen