Oriented growth of hydroxyapatite on (0001) textured titanium with functionalized self-assembled silane monolayer as template

A highly (0001) textured hydroxyapatite [Ca-10(PO4)(6)(OH)(2), HA] coating on polycrystalline titanium plate is successfully synthesized by a biomimetic process mimicking biomineralization; To simulate the first stage of biomineralization, that is, supramolecular preorganization, a template surface with highly organized arrangement of carboxyl (-COOH) and alcoholic hydroxyl (-OH) groups is prepared through self-assembly of vinyltriethoxysilane [(C2H5O)(3)SiCH=CH2, VTS] on hydroxylated titanium with strong (0001) texture, followed by oxidation of the vinyl groups (-CH=CH2) with dilute KMnO4 solution into alcoholic hydroxyl and then into carboxyl groups. The functionalized substrate can induce oriented nucleation and growth of HA with (0001) planes parallel to the substrate surface from supersaturated HA solution through interfacial molecular recognition. The mechanisms of molecular recognition are also discussed.