Evaluation of chlorine substituted hydroxyapatite (ClHAP)/polydopamine composite coatings on Ti64

Titanium (Ti) and its alloys (especially Ti-6Al-4V or Ti64) are commonly used as load-bearing implants because of their biocompatibility and resistance to fatigue and corrosion. However, Ti/alloys are bio-inert metals and not prone to osseointegration. In order to further improve the bioactivity and osseointegration of Ti64, this study evaluated the modification of the Ti64 surface with a deposited chlorine substituted hydroxyapatite (ClHAP)/polydopamine (Pda) composite coating. Pda serves as an adhesion molecule and ClHAP releases slight acidity that stimulates osteoclastic activity. The composite coating with 10-30 % ClHAP particles is shown to promote bioactivity as evidenced by osteoblast proliferation. Therefore, this coating approach may enhance osseointegration in vivo.