Selective formation of hydroxyapatite layers on titanium dioxide

Influence exerted by the structure of layers of titanium dioxide produced by chemical vapor deposition on its ability to form hydroxyapatite in Dulbecco’s phosphate-salt buffer solution was studied. The results obtained demonstrated that the surface phase composition of TiO2 determines the morphology of the mineral layer formed on its surface. The polycrystalline titanium dioxide with random orientation of anatase crystallites is the most favorable for intense nucleation and formation of homogeneous hydroxyapatite layers composed of densely packed grains with diameter of 3.0 ± 0.5 μm in Dulbecco’s solution. Textured TiO2 layers with smooth surface also resulted in that hydroxyapatite was formed. In this case, it was composed of separate coarse grains 8.0 ± 2.0 μm in size. It is the most probable that the nucleation of this mineral on the surface of titanium dioxide layers occurs by the epitaxial growth mechanism.