Synthesis of hydroxyapatite films on porous Al2O3 substrate for hard tissue prosthetics

Previous studies have shown that the porous hydroxyapatite (HA) is bioactive which can be used as a bone substitute in hard tissue prosthetics. However, as a result of its low mechanical strength, its applications are limited particularly in substitution for structural bones. To improve the mechanical properties of HA while maintaining its bioactivity, we have developed several synthesis routes by which a bioactive and strong HA composite can be processed. A thin film of hydroxyapatite has been successfully coated onto a highly porous substrate of alumina by using several solution techniques. The coated HA has been found to bond strongly to the substrate through interface diffusion. The coating has also been found to be microstructurally and chemically uniform on the surfaces of the interconnected pores in the matrix of the substrate. The mechanical property testing results have shown that the strength of the HA-coated composite has been significantly improved. The compressive strength of the HA composite has reached 10 MPa, a value ten times higher than that of porous HA. These results indicate a high potential for structural bone substitutes in the hard tissue prosthetics.