Novel hydroxyapatite coating on new porous titanium and titanium-HDPE composite for hip implant

Porous titanium (Ti) and Ti-high density polyethylene (Ti-HDPE) composite were investigated as new hip implant materials to increase the biomechanical compatibility by promoting a matching modulus of elasticity between hip stem and human bone. Surfaces of both materials were modified to increase its bioactivity and biocompatibility through electrochemical activation treatment and deposition of hydroxyapatite (HA) coating. The electrochemical activation treatment of both materials in 10 M NaOH solution created a bone-like porous nanostructure across the surfaces, thus enhancing the growth of natural bone. A top layer with nanometer-pores and TiO₂ was formed during the activation process, creating a favorable and prerequisite condition conducive to the formation of hydroxyapatite coating. Furthermore, a layer of hydroxyapatite, a bioactive and biocompatible bioceramics that is the main component of natural bone, was deposited on the porous Ti and Ti-HDPE composite through a novel chemo-biomimetic method. The formed coating was characterized through TEM as a nanometer scale crystalline.