Precipitation of hydroxyapatite film under dynamic conditions

Hydroxyapatite was synthesized by reacting Ca(HCO3)2 with (NH)2HPO4 at 25°C. It was demonstrated that, for the crystallization of hydroxyapatite on a substrate as a coating, it is important to suppress the homogeneous nucleation in the bulk volume of the precursor solution. Heterogeneous nucleation on a sol-gel derived SiO2 surface was advantageous for the deposition of film on a substrate under dynamic conditions. This approach led to the formation of a homogeneous, transparent coating (∼1 μm) of hydroxyapatite on the sol-gel derived SiO2 surface on the glass.