Functional Hybrid Materials Chapter 11.pdf

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1、38711BioactiveSol-GelHybridsJacquesLivage,ThibaudCoradinandCécileRoux11.1IntroductionThedevelopmentofbiomaterialshaslongbeenfocusedontherealizationofimplantsformedicalapplications.Suchmaterialshavetoexhibitgoodmechanicalpropertiesandtobebiocompatibleinordertobeimplantedinthehuma

2、nbody.Bioactiveimplantsbindtolivingtissuesandfavortheregenerationofdamagedtissuesorbones.Suchmaterialshavebeenrecentlyreviewedandwillnotbedes-cribedhere[1,2].Weshallfocusonnewbioactivematerialsinwhichbiospeciessuchasenzymesorwholecellsareimmobilized.Thesebioactivehybridsarenotus

3、edasimplants.Theyfindapplicationsinthefieldofbiotechnologyforthereali-zationofbiosensorsandbioreactors.Theytakeadvantageofthehighactivityofenzymes,antibodiesormicro-organismstoperformspecificreactionsthatwouldnotbepossiblewiththeusualchemicalroutes.Activebiospeciesareimmobilized

4、onorinasolidsubstrateinordertobereusableandprotectedfromdenaturation.Naturalandsyntheticpolymers(polysaccharides,polyacrylamides,alginates,etc.)arethencurrentlyusedforbio-immobilizationviacovalentbindingorentrapment.However,inorganicmaterialssuchasglassesandceramicswouldoffersig

5、nificantadvantagesoverthesepolymers.Theyexhibitbettermechanicalstrengthtogetherwithimprovedchemicalandthermalstability.Moreovertheydonotswellinmostsolvents,preventingtheleachingofentrappedbiomolecules.Combiningfragilebiomoleculeswithtoughmaterialsthenbecomesaninnova-tiveresearch

6、fieldformaterialsscientists,butglassesandceramicsaremadeathightemperature,oftenabove1000°C.Suchharshconditionsarenotcompatiblewithfragilebiomolecules.Enzymesorcellscanonlybegraftedontothesurfaceofporoussolidsandtheinorganiccarriermustbeactivatedbeforeimmobilizationviasilanizatio

7、n.Itisthentreatedwithacouplingreagent,usuallyanorganosilanesuchasγ-aminopropyltriethoxysilane,H2N–(CH2)3–Si–(OEt)3,thatbearsanorganicfunc-tionalgroupatoneendandanalkoxy-silylgroupattheotherend(Fig.11.1)[3].Thismethodhasbeensuccessfullyscaledupfromlaboratorytoindustryandseve-ralp

8、rocesseshavenowbeencommercializedformorethantwe