Organoapatite growth on an orthopedic alloy surface

We report here a method to coat orthopedic metals with the artificial bone material organoapatite. The growth of organoapatite on titanium alloy surfa ces of foils and porous cylinders involves sequential preadsorption of poly (l-lysine) and poly(L-glutamic acid) on metal, followed by exposure to orga noapatite-precipitating solutions. The organoapatite characterization of th e coating was carried out by transmission electron microscopy, electron dif fraction, scanning electron microscopy, energy-dispersive X-ray scattering, powder X-ray diffraction, FT-IR, and elemental analysis. The preadsorbed p oly(amino acids) in the form of a self-assembled bilayer of oppositely char ged macromolecules can lead to a surface coverage of titanium alloy in the range of 70-90%. The deposition mechanisms could involve the surface captur e of embryonic crystals and the nucleation of apatite on the bilayer. Bioab sorbable organoapatite could serve as a tissue-engineering scaffold for bon e regeneration into porous implants. (C) 1999 John Wiley & Sons, Inc.