Protein-hydroxyapatite Composite Coatings on TiO_2 Nanotube Layers and Bond Strength to Substrate

TiO2 nanotubes on titanium with different diameters were prepared by anodic oxidation after heat-treated at 450℃.Hydroxyapatite(HA) coatings containing bovine serum albumin(BSA) were produced on the nanostructured surface through biomimetic co-deposition.The TiO2 nanotube layers with 170nm diameter has a better mineralization ability compared that with diameter of 100nm and 50nm,And the HA formation ability is enhanced with increase of the diameters.The bonding strength of the coating to the nanotube layers with large diameter is higher than that with small diameter,and the maximal strength can reach 16.95MPa.Moreover,the pre-mineralization in vacuum signifi-cantly enhances the bonding strength,and increases growth rate of the coating.The BSA-HA coating with high bond-ing strength can fastly form on TiO2 nanotube layers by pre-mineralization in vacuum and then biomimetic co-deposition,which would be a promised method for preparing titanium-based bioacitive coatings.