Controllable Ag/Ta ratios of co-implanted TiN films on titanium alloys for osteogenic enhancement and antibacterial responses

Silver (Ag) and tantalum (Ta) ions were co-implanted into titanium nitride (TiN) films on medical titanium alloys (Ti-6Al-4V) to control the Ag/Ta ratios on the surfaces. Different ratios (e.g., Ag/Ta = 4:1, 2:1, and 1:1) were found to provide significant effects on the cytocompatibility and antibacterial properties of TiN films. The in vitro and in vivo results showed that the Ag/Ta-TiN samples with Ag+ and Ta+ co-implantation exhibited obvious inhibition of the release of toxic ions (e.g., V4+ and Al3+) from medical Ti-6Al-4V. An Ag/Ta ratio of 1:1 exhibited the highest corrosion resistance, best cell growth, outstanding antibacterial performance, and no in vivo toxicity. Ag/Ta(4:1)-TiN had the highest bacteriostatic rate of 95.7%. These results indicate that silver and tantalum co-implantation can improve the cytocompatibility and antibacterial properties of titanium alloys, and an appropriate Ag/Ta ratio is the key factor in this regard.