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Biomineralization, Biomimetic and Non- Classical Crystallization

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Biomineralization, Biomimetic and Non- Classical Crystallization BiomineralizationBiomineralizationBiomineralization,,, biomimeticbiomimeticbiomimeticandand and nonnonnon--- classicalclassicalclassicalcrystallizationcrystallization crystallization WaysWaysWaystoto tounderstandunderstand understand thethethe synthesissynthesissynthesisandand and formationformationformation mechanismsmechanismsmechanismsofof of complexcomplexcomplex materialsmaterialsmaterials HelmutHelmut CölfenCölfen Max-Planck-Institute of Colloids & Interfaces, Colloid Chemistry, Research Campus Golm, D-14424 Potsdam [email protected] CaCOCaCOCaCO333 BiomineralsBiomineralsBiominerals Coccolith (Calcite) Nacre (Aragonite) Herdmania momus (Vaterite) Characteristics of Biominerals: Complex forms generated from inorganic systems with simple structure Characteristics of inorganic crystals: Simple geometrical form but often complicated crystal structure Default: Rhombohedral Calcite ImportantImportantImportantbiomineralsbiominerals biominerals MineralMineral FormulaFormula FunctionFunction Calciumcarbonate CaCO3 Calcite Algae / Exoskeleton Birds / Eggshell Aragonite Fishes / Gravity sensor Mussels / Exoskeleton Vaterite Sea urchins / Spikes Calciumphosphate Hydroxyapatite Ca10(PO4)6(OH)2 Vertebrates / Skeleton, teeth Octa-Calciumphosphate Ca8H2(PO4)6 Vertebrates / Precursor for bone formation Silica SiO2 Algae / Exoskeleton Iron oxide Magnetite Fe3O4 Salmon, Tuna & bacteria / Magnetic field sensor Chitons / teeth EvolutionEvolutionEvolution ofofof aaa musselmusselmussel shellshellshell SEM of broken mussel shell SEM of broken mussel SEM of broken mussel shell after protein removal shell after CaCO3 removal TEM thin cut of SEM of developing SEM mature mussel shell developing mussel mussel shell shell Biominerals are often formed in confined reaction environments EpitacticalEpitacticalEpitactical matchmatchmatch betweenbetweenbetween crystalcrystalcrystal andandand matrixmatrixmatrix NacreNacre:: Periodicity in protein β-sheets and β-chitin fibers in close geo- metrical match to lattice spacing of aragonite 001 face. „„SoftSoft EpitaxyEpitaxy““ BoneBoneBone formationformationformation Amino acid sequence Sub-nm - X - Y - GLY - X - Y - GLY - X - Y - GLY - X - Y - regime (primary structure) left handed α-helix (secondary structure) 0,286 nm 2,86 nm right handed triple helix (tertiary structure) nm regime Rod-like tropocollagen 300 nm Stained collagen fibril as seen in TEM Characteristics: 300 nm 40 nm 27 nm Mineralization Collagen fibril (quatery structure) occurs in organic m regime μ 67 nm Mineralization of oriented plate-like apatite matrix crystals starting in the hole regions of the collagen fibrils. In (A), plate-shaped crystals are arranged in linear coplanar arrays forming Superstructure grooves through the fibrils. In (B) these grooves are shown to be separated by four layers of triple helical collagen molecules. Figure not formation over drawn to scale. several length mm - m regime scales Here over 9 magnitudes in Sequence of progressive bone development. Osteoblasts (OB) oriented with their backs toward the capillary vasculature (C), secrete osteoid (O) away from the vasculature, causing the formation of a bony strut (B), and length ! eventually forming a second layer of bone (B2). The stacked layer (SC), which provides osteoprogenitor cells for the process, continues to expand in the direction of bone growth. From almost atomic to macroscopic scale ToothToothTooth enamelenamelenamel Enamel Growth Tomes process direction Tomes process •• Crystallization and assembly of fibers into rods on the μm scale •• Ordered layer structure of rods provides mechanical strength •• Permanent further crystallization and density increase up to 95 wt.-% mineral Crystallization often occurs highly directed MagnetotacticMagnetotacticMagnetotactic bacteriabacteriabacteria Nucleation on inside wall of vesicle Linear organization for magnetic compass 10 nm PhasePhasePhasetransitionstransitions transitionsandand andmatrixmatrix matrix assistedassistedassisted nucleationnucleationnucleation Adapted from S.Mann IMPRS lectures, Golm 2003 Sequence of kinetic inhibitions and phase transformations, resulting in high selectivity degree in crystal structure and composition Direct mechanisms to increase S: Ion pumping + redox Ion complexation/decomplexation Enzymatic regulation Indirect mechanisms to increase S: Ion transport Water extrusion Proton pumping GeneralGeneralGeneralbiomineralizationbiomineralization biomineralization featuresfeaturesfeatures • Uniform particle size • Well defined structure and composition • High levels of spatial organization • Complex morphologies • Controlled aggregation and texture • Preferential crystallographic orientation • Higher order assembly • Hierarchical structures Adapted from S.Mann IMPRS lectures, Golm 2003 KnownKnownKnown mechanismsmechanismsmechanismsofof ofBiomineralizationBiomineralization Biomineralization • Stabilization • Morphology control by selective adsorption • Control of the crystal modification by „Soft Epitaxy“ • Static templates • Confined reaction environments • Adaptive construction and synergistic effects • Structural reconstruction • Higher order assembly PolymerPolymer structuresstructures asas staticstatic templatestemplates PS-PAA Gel + Fe3O4 Control Fe2+-loaded Magnetic gel Biomimetics Biomineral Zoom 1 μm Mollusc tooth Homogeneous 38 nm Fe3O4 15 - 35 nm in Polysaccharide - Protein Gel Templated 17 nm M. Breulmann, H.P. Hentze DoubleDouble hydrophilichydrophilic blockblock copolymerscopolymers Molecular tool: = hydrophilic, interacting with mineral Handle Head = hydrophilic, non interacting with mineral Amphiphilic behaviour induced in presence of mineralic surfaces allows - Size/shape control - Stabilization AdvantageAdvantage ofof DHBCDHBC designdesign forfor CaCOCaCO Advantage of DHBC design for CaCO33 PMAAPMAA PEOPEO--bb--PMAAPMAA PE block too long, PE block and stab. PE block too short, PE block far too short, stab. block too short block good ratio stab. block too long stab. block too long DoubleDouble hydrophilichydrophilic blockblock copolymerscopolymers Precursor Polymers Functionalities OH COOH PEG-b-PEI (Linear and branched) SO3H PEG-b-PMAA PO3H2 PO4H2 CH3SCN PEG-b-PB NR3, HNR2, H2NR Modular Synthesis Hydrophobic M = 3000 – 10000 g/mol M. Sedlak, M. Breulmann, J. Rudloff, P. Kasparova, S. Wohlrab, T.X. Wang BaSO Morphogenesis at pH 5 BaSOBaSO44 MorphogenesisMorphogenesisat atpH pH 55 2μm 0.5μm PEG-b-PEI-SO3H PEG-b-PMAA-Asp 2μm 0.5μm No additive 2μm PEG-b-PEI-COOH PEG-b-PMAA-PO H L.M.L.M. QiQi PEG-b-PMAA-PO3H2 CdS + PEO-b-PEI CdSCdS+ + PEOPEO--bb--PEIPEIbranchedbranched L.M.L.M. QiQi • Particle size adjustable 2 - 4 nm • Monodisperse stable particles • No photooxidation • Branched PEI more effective than linear or dendrimer 2.0 0.05 g/l 1.8 0.10 g/l 1.6 0.25 g/l 0.50 g/l 1.4 1.00 g/l 1.2 1.0 0.8 Absorbance 0.6 0.05 g/l PL Intensity (a.u.) Intensity PL 0.10 g/l 0.4 0.25 g/l 0.2 0.50 g/l 1.00 g/l 0.0 250 300 350 400 450 500 550 400 450 500 550 600 650 Wavelength (nm) Wavelength (nm) SelectiveSelectiveSelectiveAdsorptionAdsorption Adsorption Gold crystallized in presence of PEG-b-1,4,7,10,13,16-Hexaazacycloocatadecan (Hexacyclen) EI macrocycle Interference patterns due to deformations in sub-Angström range Very thin platelets 200 nm Very thin platelets with Au (111) surface and exposed 111 surface, adsorbed hexacyclen Well developed plasmon molecule in vacuum band in UV/Vis S.H.S.H. YuYu SurfacesSurfaces asas staticstatic templatetemplate CaCO3 + O m n OPO(OH)2 PEG(m)-b-PHEE(n)-(PG rad%) J.J. RudloffRudloff 2+ - CaCO3(s) + CO2(g) + H2O(l) Ca (aq) + 2 HCO3 (aq) 50 μm 50 μm 50 μm StructuralStructuralStructural reconstructionreconstructionreconstruction pH = 5 BaSO4 with PEG-b-PMAA-PO3H2 Parallel cut to to fiber axis Perpendicular cut to fiber axis Fiber axis is [210] Diameter 20 - 30 nm Bundles of single crystalline fibers L.M.L.M. QiQi StructuralStructuralStructural reconstructionreconstructionreconstruction pH = 5 BaSO4 fibers obtained in the presence of PEG-b-PMAA-PO3H2 on carbon films with an aging time of 5d. •• Heterogeneous nucleation on carbon films •• Perfectly flat surface of growth edge due to surface minimization L.M.L.M. QiQi CrystallographicallyCrystallographically orientedoriented nanoparticlenanoparticle attachmentattachment Single crystalline anatase TiO2 particles hydrothermally synthesized in 0.001 M HCl Topotactic particle attachment at high energy surfaces (112) a) Single primary crystal, b) four primary crystals forming a single crystal via oriented attachment, c) Single crystalline anatase particle R.L. Penn, J.F. Banfield; Geochim. Cosmochim. Acta. 63 (1999) 1549 - 1557 1) 2) 3) L.M.L.M. QiQi Nucleation of amorphous nanoparticles, polymer stabilization 4) 5) 6) 7) - Crystallization of amorphous particles, directed particle fusion Perfect Single Crystals Fiber Bundles: Elongation along [210] [2 1 0 ] 500nm <001> 4 -20 400 4-10 420 410 2-20 200 2-10 220 210 0-20 020 -2-10 -2-20 -200 -220 -210 XY -4-10 -4 -20 projection -400 S.H.S.H. YuYu BaSO4, 2 mM, polyacrylate ( Mn = 5100) StructuralStructuralStructural reconstructionreconstructionreconstruction 0.11mM, pH = 5.5, 25 °C 10 μm 1 μm Cuttlefish bone β-Chitin + aragonite 100 μm 2 μm S.H.S.H. YuYu HigherHigher orderorder assemblyassembly [PEG-b-PMAA] = 1 g/l, 30 min 60 min [CaCO3] = 8 mM, pH = 10 •• Chains of aggregated amorphous nanoparticles •• Dumbbell 100 nm 100 nm shaped and spherical 90 min 120 min aggregates •• Nanoparticle crystallization Primary crystals 40 nm 10 μm 10 μm Zoom L.M.L.M.
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