BEH.462/3. 962J Molecular Principles of Biomaterials Spring 2003 Hypertrophic chondrocytes/ odontoblasts Hydroxyapatite lon influx D CaHPO4 D crystallization nucleation Matrix vesicles Extracellular matrix lon channels Transport proteins synthetic( biomimetic) vesicular mineralization Vesicular mineralization nre 2, Porous vater on of vaterite microsph in carbon dioxide(A). The droplets become super- tanned water interface( B), which leaves an im- prrt as the emulsion is air dried (C) falbwiag eless af trpe (Green et al. 2002) chemistry of CaCO3 deposition in vesicles o Ca(aq)+ 2HCO3(aq)-> CaCO3(s)+ CO2 (aq)+ H2O [H2OJ[COzaallCaco3sI = constant [Caa I[HCO3 o e.g. algae: remove dissolved CO2 to induce more CaCO3 precipitation o supersaturation highest near bubbles of CO2, nucleation preferentially at surface of vesicle and grows Lecture 11-Inorganic biomaterials 7of12BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Lecture 11 – Inorganic Biomaterials 7 of 12 Matrix vesicles Extracellular matrix Hypertrophic chondrocytes/ odontoblasts Ion channels Transport proteins - - - - - - - - - Acidic phospholipids Ca++ Ca++ PO4 - Ion influx CaHPO4 nucleation Hydroxyapatite crystallization synthetic (biomimetic) vesicular mineralization Vesicular mineralization (Green et al. 2002) • chemistry of CaCO3 deposition in vesicles: o Ca++(aq) + 2HCO3 - (aq) -> CaCO3(s) + CO2(aq) + H2O o Keq = [H2O][CO2(aq)][CaCO3(s)] [Ca(aq) ++ ][HCO3(aq ) ] 2 = constant o e.g. algae: remove dissolved CO2 to induce more CaCO3 precipitation o supersaturation highest near bubbles of CO2, nucleation preferentially at surface of vesicle and grows inward