Preparation of Silicon-Containing Apatite Coating on Titanium

A silicon-containing apatite layer was prepared on a metallic titanium substrate coated with a silica layer. The silica layer on a titanium substrate was derived from water glass through heat-treatment at 300 degrees C for 2 hr and subsequent acid-treatment using 0.1 N-HCl at 50 degrees C for 2 hr. The silica layer was homogeneously coated with nano-sized vaterite powders (similar to 0.5 mu m in diameter). The vaterite coating was achieved by utilizing the interaction of surface potentials between the positively charged vaterite and the negatively charged silica layer. After soaking the sample in simulated body fluid at 37 degrees C for 3 days, hydroxyapatite (HA) formed on the surface of the silica-coated titanium. The HA layer was found to include a trace amount of releasable silicon, which may enhance the osteoblast proliferation.