BEH.462/3. 962J Molecular Principles of Biomaterials Spring 2003 Lecture 12: Organic templating of inorganic materials and bone biomimesis Last time interfacial biomineralization and biomimetic inorganic chemistry Today biological strategies for inorganic templating by organic materials Biomimetic plate material Biomimesis of bone Reading S Mann, 'Biomineralization: Principles and Concepts of Bioinorganic Materials Chemistry, Ch 6, pp. 89-124(2001) Biological strategies for inorganic templating by organic materials Alteration of barriers to nucleation Organic surfaces alter free energy barrier to nucleation(Mann Science 1993) △Gn AG 级=级 Fig. 2. Diagrammatic rep- AG and presence(state 2)of ganic surface (b)depending on the levels of recogn fidelity of matrix production, both of which may be influenced by genetic. metabolic, and environmental processes o Reminder of free energy of nucleation(homogeneous, but principle applies to heterogeneous surface nucleation as well) △Gm=△Gme-△Ghak=4m-m Where AGv is the free energy change for formation of the solid per mole from the ions, and Vm is the molar volume of the nucleated solid Lecture 12-Inorganic biomaterials 1of13
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Lecture 12: Organic templating of inorganic materials and bone biomimesis Last time: interfacial biomineralization and biomimetic inorganic chemistry Today: biological strategies for inorganic templating by organic materials Biomimetic organic template materials Biomimesis of bone Reading: S. Mann, ‘Biomineralization: Principles and Concepts of Bioinorganic Materials Chemistry,’ Ch. 6, pp. 89-124 (2001) Biological strategies for inorganic templating by organic materials Alteration of barriers to nucleation • Organic surfaces alter free energy barrier to nucleation (Mann Science 1993) ∆G* ∆Gnuc o Reminder of free energy of nucleation (homogeneous, but principle applies to heterogeneous surface nucleation as well): ∆Gnuc = ∆Gsurface − ∆Gbulk = 4πr 2 σ − 4 3 πr 3 ∆Gv Vm Where ∆Gv is the free energy change for formation of the solid per mole from the ions, and Vm is the molar volume of the nucleated solid Lecture 12 – Inorganic Biomaterials 1 of 13
BEH.462/3. 962J Molecular Principles of Biomaterials Spring 2003 How are free energy barriers modified by organic templates?(Mann 1993)Complementarity in 1. Surface lattice geometries 2. Spatial charge distributions 3. Polarity of hydration layers 4. Defect sites 5. Bonding chemist Coordination environment of metal ion in crystal mimicked by binding to organic surface groups Fig. 6.28 Free energy curves for nucleation in the absence (1) and presence o Matching lattice geometries Organic templating layer 5 New crystal Nucleation of the calcite 110 face under car- boxylate monolayers( B)Nucleation of the cal- cite(001)face under sulfate monolayers Mann et al. 1993 itching charge distributio Case of calcium cabonate: different crystal structures and crystal orientations nucleated on different charge surfaces Lecture 12-Inorganic biomaterials 2of13
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 • How are free energy barriers modified by organic templates? (Mann 1993) Complementarity in: 1. Surface lattice geometries 2. Spatial charge distributions 3. Polarity of hydration layers 4. Defect sites 5. Bonding chemistry Coordination environment of metal ion in crystal mimicked by binding to organic surface groups o Matching lattice geometries: Organic templating layer New crystal (Mann et al. 1993) o Matching charge distributions: Case of calcium cabonate: different crystal structures and crystal orientations nucleated on different charge surfaces Lecture 12 – Inorganic Biomaterials 2 of 13
BEH.462/3. 962J Molecular Principles of Biomaterials Spring 2003 Table 1. Oriented nucleation of inorganic crystals under Langmuir monolayers Monolayer Metal(mM) Mineral Nucleated face 7-10 Calcite {10 46 Vaterite CHa(CH,)1NH 4-10 Vaterite CHa(CH,),OS CH3(CH2)19PO3 CH3(CH2)17OH 4-10 Nonoriented inhibited C27HasOH 4-10 Nonoriented Baso CH3(CH2)1gOSO 0.15 B (100 CH3(CH2)1 2 0.15 Barytes (100 CHa (CH,),COo 0.15 (010) CasO a CHa(CH,)NH 2040 Gypsum (010)+{T03} CH3(CH2)( 2040 Gypsum (010)+{103} CH3(CH2)gpO 20-40 Gypsum 010)+{103} ypsum CH3(CH2)1OH 20_40 Fig. 4.23 Computer model showing side view of the calcite (110) face with Fig. 4.20 Drawing of calcite (110) crystal face with surface-adsorbed malonate o Templates used by nature Proteins polysaccharides o Process is universal for templated nucleation Material: carbonates, phosphates silica, ice Template: carboxy-rich moieties hydrogen-bonding moieties o E.g. Aspartic acid, glutamic acid, phorphorylated residues for carboxy-rich o E.g. polysaccharides, Ser, Thr for hydrogen-bonding residu (refs in Mann 1993) Lecture 12-Inorganic biomaterials 3of13
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 o Templates used by nature: Proteins Lipids polysaccharides o Process is universal for templated nucleation: Material: carbonates, phosphates silica, ice Template: carboxy-rich moieties hydrogen-bonding moieties o E.g. Aspartic acid, glutamic acid, phorphorylated residues for carboxy-rich o E.g. polysaccharides, Ser, Thr for hydrogen-bonding residues (refs in Mann 1993) Lecture 12 – Inorganic Biomaterials 3 of 13
BEH.462/3. 962J Molecular Principles of Biomaterials Spring 2003 control of nucleation and growth organic templates can preferentially nucleate the inorganic without ordering or aligning it o e.g. silica deposition in radiolarians and diatoms Templated crystal growth needs both recognition of individual molecules and a larger underlying lattice to drive directed nucleation o Obtaining periodicity in organic template How nature does it: secondary structures(nm-scale organization ): a helix, B sheet On larger length scales, cells control deposition Localization and orientation of proteins and phospholipids Secondary, tertiary, and quarternary protein structures are involved to provide the 'lattice for templating crystals Ordered template geometries may allow selection of crystal polymorph o Requires flat, ordered surface in 2D o E.g. for CaCO3: calcite vs aragonite vs vaterite Calcium carbone( CaCO3) crystal structures calcite (http://ruby.coloarado.edu/-smyth/min/minerals.html Example: nacre o Layered CaCO3 structure of seashells(mollusks, etc. Lecture 12-Inorganic Biomaterials 4of13
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 control of nucleation and growth • organic templates can preferentially nucleate the inorganic without ordering or aligning it o e.g. silica deposition in radiolarians and diatoms • Templated crystal growth needs both recognition of individual molecules and a larger underlying lattice to drive directed nucleation o Obtaining periodicity in organic template: How nature does it: secondary structures (nm-scale organization): α helix, β sheet On larger length scales, cells control deposition • Localization and orientation of proteins and phospholipids Secondary, tertiary, and quarternary protein structures are involved to provide the ‘lattice’ for templating crystals • Ordered template geometries may allow selection of crystal polymorph o Requires flat, ordered surface in 2D o E.g. for CaCO3: calcite vs. aragonite vs. vaterite Calcium carbone (CaCO3) crystal structures calcite aragonite (http://ruby.coloarado.edu/~smyth/min/minerals.html) Example: nacre o Layered CaCO3 structure of seashells (mollusks, etc.) Lecture 12 – Inorganic Biomaterials 4 of 13
BEH.462/3. 962J Molecular Principles of Biomaterials Spring 2003 Plate-like aragonite( CaCO3) crystals form the inner layer of seashells: ( scale 6.38 Structural model for geometric matching in shel nacre. R, 6.39 Role of IAsp-XI domains in Ca"binding and oriented nucleation in shell nacr Biomimetic organic templated materials Patterned surface mimics of templated inorganics Directed mineral deposition by patterned surfaces presenting organized charged groups2 Work of Joanna Aizenberg at Bell Labs °Neh2p HS(CH2)2OH on Au (Ca1210 mM: N= 100 (Ca-1=10 mM. N =100 PDMS stamps with anous relief structures th HS(CH2)isCO2H Nucleating plane (012) Nucleating plane(01 Microcontact print HS(CH2)15CO2H Ca"=10 mM: N= 100 ca21=100mMN=10.000 CO,H-terminated SAM Wash with HS(CH?)sCH3 CHa-terminated SAM =10m crystallization solution HSC.DH, The density and tim d batres n the tno an the ATm wh wanou oates d aceton N-100"nem and 以以以 PDMS supports Boomed o AfHL c Amys df ortet wth ne ceret a ragmensinght wow he tomson d urmoemen 33sof.om (Aizenberg et al. 2000) Lecture 12-Inorganic biomaterials 5of13
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Plate-like aragonite (CaCO3) crystals form the inner layer of seashells: (scale bar 1 µm) Biomimetic organic templated materials Patterned surface mimics of templated inorganics1 Directed mineral deposition by patterned surfaces presenting organized charged groups2,3 Work of Joanna Aizenberg at Bell Labs: (Aizenberg et al. 2000) Lecture 12 – Inorganic Biomaterials 5 of 13
BEH.462/3. 962J Molecular Principles of Biomaterials Spring 2003 Supersaturation theory/model 一 Slowly nude crystal (crystals). The profiles were derived using the diffusor ciat=Dac/ax, and assuming zero concentration of solution at the the crystallizing region( that is, assuming that all the ions that reach the the crystal stick irreversibly). The dashed line corresponds tothe conc b the saturated solution, Caat be low which nucleation on the slowly surface does not occur In the regiona where co)/a, where c >Cs. For the nucleation on the methyl-term faces, csar is -2. 5 mM. b, SEM image of the pattern of calcite crystals methy terminated surface with one isolated carboxylate termina showing the depletion distance, Io e 80Hm, in agreement with the v 100 um)calculated assuming Cout= 25 mM, Css= 2-2.5 mM and cr Concentraton time t= 30 min, c, Calculated profiles of the concentration of the solution in the vicinity of an array of rapidly nucleating regions with Aray of rapid p<2g. The effective concentration(bold lines)over the entire slowly region is then below Caat. Crystallization will only take place on nucleating regions, as shown in Fig 1c Solution is effectively undersaturated B 1 0N ★★ Lecture 12-Inorganic Biomaterials 6of13
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Supersaturation theory/model Lecture 12 – Inorganic Biomaterials 6 of 13
BEH.462/3. 962J Molecular Principles of Biomaterials Spring 2003 Mimicking the silica deposition of diatoms Fig. 7. 15 Stages in the morphogenesis of the diatom frustule. See text for details. nanovesicles SDV-silica deposition vesicles AV- aleolar vesicles PL-plasmalemma(lipid bilayer cell wall) ER-endoplasmic reticulum Disk-shaped diatom 31 SSKKSGSYSGSGSKGSKRR Amine side chains Si substrate (Brott et al. 2001 Lecture 12-Inorganic Biomaterials 7of13
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Mimicking the silica deposition of diatoms nanovesicles SDV - silica deposition vesicles AV - aleolar vesicles PL - plasmalemma (lipid bilayer cell wall) ER - endoplasmic reticulum Disk-shaped diatom Silaffin cationic polypeptide lines SDVs and provides a nucleating surface for silica deposition in the diatom: SSKKSGSYSGSGSKGSKRR Amine side chains (Brott et al. 2001) Si substrate (tri-acrylate) Lecture 12 – Inorganic Biomaterials 7 of 13
BEH.462/3. 962J Molecular Principles of Biomaterials Spring 2003 silaffin peptide in grooves of gel surface . emea Reverse recognition: Using synthetic inorganic materials to quide localization of biological targets" 回 Figure 4 Phage recognition of semiconductor heterostructures a-C, Fuorescence mages related to GaAs recognition by phage a, Control exper iment: no phage is present, but primary antibody and streptavidin-tetramethryl rhodamine(MR) are present b, The GaAs clone G12-3 was interacted with a substrate patterned with 1-um GaAs lines and 4-um SiO, spaces. The phage were then fluorescently labelled with TMR. The G12-3 cone specically recognzed the GaAs and not the siO, surface; scale bar, 4 um. A diagram of this recognition process is shown in d, in which phage specifically attach to one semiconductor rather than another. in astructure. C, An SEM image of a heterostructure containing altemating layers of GaAs and AlagdGao a As, used to demonstrate that this recognition is element-specific. The cleaved with G12-3 phage, and the phage was then tagged with 20-nm nanoparticles (shown arrowed in c) are located on GaAs and nota 500nm. e, Diagram illustrating the use of this specificity to desig heterostructures using proteins with multiple recognition sites. (Belcher lab) Lecture 12-Inorganic Biomaterials 8of13
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 + Si(OH)4 (aq) [10 min. room temp] Silaffin peptide in grooves of gel surface Reverse recognition: Using synthetic inorganic materials to guide localization of biological targets4 (Belcher lab) Lecture 12 – Inorganic Biomaterials 8 of 13
BEH.462/3. 962J Molecular Principles of Biomaterials Spring 2003 Biomimesis of bone Structure of human bone 2 component model of organic matrix the organic matrix within bone is composed of 2 classes of organic materials Nucleating surface Fig 6.4 Two-component model of the organic matrix o crystals grown out from nucleating surface composed of acidic macromolecules component Composition Water Framework Hydrophobic/cross-linked Matrix structural integrity macromolecules proteins and polysaccharides Acidic Glycoproteins and Nucleating surface for macromolecules hydroxyapatite components in human bones: System Framework macromolecules Acidic macromolecules Bone and dentine Cross-linked type I collagen Glycoproteins Ostoepontin( these rich in Osteonectin Asp and Glu) Chondroitan sulfate Keratin sulfate Tooth enamel Amelogenin Glycoproteins enamelin Organization of organic matrix framework macromolecules o tropocollagen cross-linked at helix ends in staggered arrangement maximizes interfilament cross-links each tropocollagen helix is 280 nm long o gaps between helices 40 nm x 5 nm hole zones Lecture 12-Inorganic biomaterials 9of13
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Biomimesis of bone Structure of human bone 2 component model of organic matrix the organic matrix within bone is composed of 2 classes of organic materials o crystals grown out from nucleating surface composed of acidic macromolecules component Composition Water solubility Role Framework macromolecules Hydrophobic/cross-linked proteins and polysaccharaides Low Matrix structural integrity Acidic macromolecules Glycoproteins and proteoglycans High Nucleating surface for hydroxyapatite components in human bones: System Framework macromolecules Acidic macromolecules Bone and dentine Cross-linked type I collagen Glycoproteins: fibrils Ostoepontin (these rich in Osteonectin Asp and Glu) Proteoglycans: Chondroitan sulfate Keratin sulfate Tooth enamel Amelogenin Glycoproteins: enamelin Organization of organic matrix framework macromolecules o tropocollagen cross-linked at helix ends in staggered arrangement maximizes interfilament cross-links o each tropocollagen helix is 280 nm long o gaps between helices 40 nm x 5 nm ‘hole zones’ Lecture 12 – Inorganic Biomaterials 9 of 13
BEH.462/3. 962J Molecular Principles of Biomaterials Spring 2003 Human bone framework macromolecules aggered arrangement of tropocollagen(triple helices)maximizes interfilament ∴∵ Fig.6.11 Location of cross-links between the carboxy ICI and amino IN) terminal regions of adjacent tropocollagen filaments in collagen fibrils 回= mineralized colagen crystal microfiber -] cross-section of the microfiber glycoproteins bind collagen o exact role/organization is not yet known structural hierarchy o TEM micrograph in lamellar bone paper showing plywood structure Lecture 12-Inorganic Biomaterials 10of13
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Human bone framework macromolecules: Staggered arrangement of tropocollagen (triple helices) maximizes interfilament cross-links: glycoproteins bind collagen o exact role/organization is not yet known structural hierarchy o TEM micrograph in lamellar bone paper showing plywood structure5 Lecture 12 – Inorganic Biomaterials 10 of 13
