第五章-生物矿化

5.15.25.35.154CaCO3//Mg(Mg,Ca)CO3Coccolithophoresscalebar,3µmscalebar,8µmDayNightFromNature2001,Vol.212,p318Ophiocomawendtii/1cmOphiocomapumila1cmDayNight1cm10µm10µmOphiocomawendtiOphiocomapumila1cmLNPNervebundleLensPigment1µmCaCO3CaCO3CaCO3.H2O/Ca10(PO4)6(OH)2/Ca8H2(PO4)6CaSO4.2H2OSrSO4BaSO4LoxedesXenophyophoresCharaCaC2O4.H2O//WeddelliteCaC2O4.2H2O//(R)SiO2.nH2ODiatomsChoanoflagellatesRadiolariansChrysophytsLimpetsPlantsRadiolarianmicro-skeleton,Scalebar,10µmDiatomshell,scalebar,1µmThechemicalnatureofamorphoussilicaFe3O4/5Fe2O3.9H2O/500nm20nm4500•••••5.2selfassemblyAFPFromNature2000,Vol406p325ββ0.464x0.744nmFrom:Nature2000,Vol.406,p.322.βCaCO3CaCO3calcitearagonitevateriteCa2+,CO32-CaCl2Na2CO3CaCO3CaCO3CaCO3∆GN=∆GS–∆GB∆GS=4πr2σ(σ)∆GB=4πr3∆GV/3(∆GV)∆GN=∆GS–∆GB−∆GI∆GI-∆GNr*1StacksofmineralsOrganicmatrixframeE:envelopeS:sheete.g.nacreinseashells.OrganicmatrixframeStacksofminerals2Cross-sectionthroughasinglematrixsheet~10nma.b.glycoproteinsaspartate(Asp)30%glutamate(Glu)17%e.g.nacrein)••••Framework:silkfibroin-likeproteinFunctionalacidicmacromoleculesOC_OCa++Ca++Ca++OC_OOC_OOC_O(a)Inthepresenceofsea-urchinprotein(c)Intheabsenceofproteins(d)InthepresenceofseashellproteinCaCO31.CaCO3a.Ca2+,CO32-β-(β-cyclodextrin)25oCCaCO3β-0012Ca2+,CO32-(hepatin),(pepsin),(solublestarch)25oCCaCO3SubstrateCrystals2.CaCO3::SAMs(Self-AssembledMolecules).Aizenberg(PatternedCrystalNucleation)1.PDMSmold2.StampingSAMsontoAu-coatedSi3.SAMsself-assembleonAusurfaceCOOHSH--------Ca2+Ca2+Ca2+4.CrystalgrowthinsolutionssupersaturatedwithCa2+andCO32-:(1)(2)(3)ZnOFromNatureMaterials2003,Vol.2,p.821–826aZnObcdZnOZnO0001a=0.3252nmc=0.5213nmZnO••:C6H8O7Step1:ZnOStep2:30mlZn(NO3)2(0.01–0.06M)60C3ZnOStep3:ZnO(001)001ZnOZnOZnO5.3VolumeFraction,%TensileModulus,GPaBendingStrength,MPaWorkofFracture,J/m2Bone41162701700Dentin4812250550Enamel924576200Nacre9564200600-1240Alumina350100-10007(K1c,MPa.m1/2)Al2O3:3.5CaCO3:0.15-0.8Nacre:8~10InelasticMaterialsStressDistancetotheNotchElasticMaterialsσσAl2O31.“”-CrackCrackBridgingCrackbridge2.a.(001)b.c.:••CrackB4CAl(~5µm)1:•B4C•1100Al•B4C•200µm••5µmAl•AlAl•12MPa.m1/218MPa.m1/2•SiCC(~25µm)2•SiC•C•SiC•~200µm•••2040°C30min•3.6MPa.m1/217.7MPa.m1/2•28J/m26152J/m2SiCC(~25µm)crackLoadDeflectionStephenMann,Biomineralization:PrinciplesandConceptsinBioinorganicMaterialsChemistry,OxfordUniversityPress2001.