(1. College of Mechanics and Materials, Hohai University, Nanjing 211100, China) （2. Ocean and Offshore Engineering Research Institute of Hohai University, Nantong 226019, China)
Titanium alloys have been widely used in the field of biomedicine due to their excellent mechanical properties and good biocompatibility. With the continuous improvement of performance requirements for implants, new medical titanium alloys with excellent mechanical property and high strength modulus ratio have been gradually developed. At the same time, due to the osseointegration problems of titanium alloys such as poor surface cell adhesion, surface modification to improve the biocompatibility of titanium alloys has become the research focus of medical titanium alloys. This article summarized the development progress of biomedical titanium alloy for bone implants and common surface modification coatings, focusing on the introduction of hydroxyapatite (HA) coating, chitosan coating and the TiO2 nanotube array coating on the surface of titanium alloy prepared by anodic oxidation. The effect of microstructure, crystal type and ion doping, etc. on the surface wettability, cell proliferation and differentiation of titanium alloy was summarized. It was pointed out that improving the osseointegration ability of implants and achieving functionalization of the new low elastic modulus titanium alloy by preparing surface modification coatings or combining a variety of surface modification methods would be the main direction of alloy surface modification of future medical titanium alloys.