蚕丝和蜘蛛丝纤维从溶解性蛋白到超级纤维

Silk:FromSolubleProteintoExtraordinaryFiberJiangYanke2012-02-02#Silk:FromSolubleProteintoExtraordinaryFiber1.Spidersilk2.Silkwormsilk3.Theformationofextraordinaryfibersfromsolubleprotein#Examplesofsilkfibersproducedbysilkwormsandspidersandaschematicillustration.#Fibersproducedbysilkwormsandspidersarenaturalcomposites#1.SpidersilkThepropertiesofspidersilkThecategoryofspidersilkThestructureofspidersilk#Thepropertiesofspidersilk•ExtremelyhighmechanicalstabilityDraglinesilkisfivetimestougherthansteelbyweightandeventhreetimestougherthanman-madesyntheticfibers,suchasKevlar49.•Supercontraction“Worn-out”silkthreadswithinaspidersnetarerenewedinthemorningdew,andthewebregainsitsrigidity.•Biocompatibility,smoothnessandthinnessincomparisontootheravailablematerials#Themechanicalpropertiesofanimalsilksincomparisonstootherman-madeandnaturalmaterials#ThecategoryofspidersilkSummaryofspidersilks,theirfunctions,andglandsoforiginforthegoldenorbweaverNephilaclavipesSevensetsofsilk-producingglandsinwhichtheconstituentsilkproteinsaresynthesizedbyepithelialcellsbeforebeingspunassevendifferenttypesofsilk,eachpossessingdifferentfunctionalproperties.#Spidersilk#SpidersilkThetwomostimportantsilks(majorampullateandflagelliformsilkfibers)inorbwebsspunbyAraneusdiadematusspiders.#MajorampullatesilkCore-shelltypestructureofsilkfibersScanningelectronmicroscopyimageofspidersilktakenfromawebofthegardenspiderAraneusdiadematus.#2.SilkwormsilkPropertiesSilkproteinApplications#Thepropertiesofsilkwormsilk•NativesilkfiberfromBombyxmorisilkwormisknownasimportantbiomaterialsinmanyapplicationsincludingbiomedicalsutures,tissueengineeringscaffoldsfortendon,bone,teeth,ligamentsandotherbioengineeredclinicalproducts•characteristicstrength,moistureabsorbanceandluster•Shortcomingsastheyarepronetophotoyellowing,andhavepoorrubresistanceandwrinklerecovery•Itsgoodmechanicalstrength,waterstability,thermalproperties,surfaceroughnessandbiocompatibility.#CompositematerialsbasedonsilkproteinsMan-madecompositematerialsbasedonsilkproteinsandsyntheticpolymers•Non-biodegradablesyntheticpolymers:carbonnanotubes,nylon,poly(acrylamide),poly(acrylonitrile),poly(epoxides)et.al.•Biodegradablesyntheticpolymers:poly(asparticacid),poly(ε-caprolactone),poly(lactic-co-glycolicacid),poly(lacticacid),poly(urethane)–pellethaneet.al.Man-madecompositematerialsbasedonsilkproteinsandbiopolymers•Polysaccharides:alginate,cellulose,chitin,cellulosexanthate,chitosan,hyaluronicacid•Otherproteins:collagen,enzymes,gelatin,greenfluorescentprotein,growthfactors,fibroinsofdifferentspecies,keratin,sericin,spidroinsofdifferentspecies.Man-madecompositematerialsbasedonsilkproteinsandinorganicparticles•Metalnanoparticles:Silvernanoparticles,Goldnanoparticles,Transitionmetaloxides/sulfides•Biominerals:Calciumcarbonate,Calciumphosphate,Silica#ApplicationsofcompositematerialsbasedonsilkproteinsTextilesSyntheticpolymers:MixingB.morifibroinwithpoly(acrylonitrile)notablyimprovedthefiberswaterabsorptionandreducedtheirtendencytocollectstaticelectricityBiopolymers:Fiberscomposedof30wt%B.morifibroinand70wt%cellulosehadimprovedelasticmoduliattheexpenseofbreakingstrengthandyieldstressrelativetoequivalentfibersproducedsolelyfromcelluloseMetalnanoparticles:B.morifibroincoatedwithsilvernanoparticlestopreventthegrowthofthegrampositivebacteriumStaphylococcusaureusonthesurfaceofthesilkfabricSuturesanddressingsforwounds•Theirstrength,biocompatibilityandlowimmunogenicity.•Sutures,wounddressings,tissuescaffolds,biocompatiblecoatings,drugdeliveryMaterialswithnovelelectronic,magneticandopticalpropertiesEnzymaticallyactivebiomaterials----biosensors#Silkproteinfromsilkworms•FibroinThewater-insolubleprotein,frommulberrysilkworm,hasbeenrecognizedasasubstrateforgrowthandadherenceofcellsinculture•SericinThewater-solublecomponentofsilk,fromthemulberrysilkworm,isusedasabiomaterialduetoitsantibacterialandUVresistantpropertiesSericinisalsoreportedtosuppressinvitrolipidperoxidationandpossessesantitumorpropertieswithnoimmunogenicityIndeed,sericinhaspreviouslybeenreportedtopossessphotoprotectiveeffectagainstUVB-inducedacutedamageandcoloncarcinogenesis.#Silkfibroin•Heavy(H)fibroinchain－5,236residues391kDa•Light(L)fibroinchain－266residues28kDa•P25glycoprotein－twoformsdifferingbyglycosylation•H-fibroin,L-fibroin,andP25areassembledinelementarysecretoryunitsintheratio6:6:1•H-LfibroinarelinkedbyasingledisulfidebondbetweencysteineresiduesintheC-terminiofeachoftheseproteins.P25associateswiththeH-Lcomplexprimarilybyhydrophobicinteractions.#L-fibroinispredominantlyhydrophobicbutformationofaninternaldisulfideloopandthedisulfidebondtoH-fibroinarelikelytoexposethehydrophilicN-terminusofthemolecule.GlycosylationofthispartofL-fibroininP.xuthusfurtherincreaseshydrophilicity.P25consistsofalternatinghydrophobicandhydrophilicareaswithconsiderablenumberofchargedresidues.Thesolubilityofmatureproteinisenhancedbyglycosylation.AnalysisofknownH-fibroinsindicatesthatthenatureofinteractingmotifs,whichdeterminethesecondaryproteinconformation,iscrucial,bu