Effects of Zn and Ag Ratio on Cell Adhesion and Antibacterial Properties of Zn/Ag Coimplanted TiN

Titanium alloy (Ti-6Al-4 V) has good biocompatibility and mechanical properties, but its biologically inert and poor antibacterial property limit its application in the field of medical implants. In this study, titanium nitride (TiN) is first deposited on the surface of titanium alloy to wrap toxic elements (for example, vanadium). Then Zn and Ag ions with different ratios are simultaneously implanted into TiN via a plasma immersion ion implantation (PIII) system. X-ray photoelectron spectrometer proves the presence of Zn, Ag, and TiN on the surface of Zn/Ag-TiN. Protein adsorption suggests that, with the increase of Zn ratio, the adsorption ability is enhanced. Biological assays indicate that Zn/Ag(1/0.3)-TiN has the best cell proliferation and adhesion, because it has a larger ratio of Zn. Zn/Ag(1/2)-TiN has the best antibacterial effect and followed by Zn/Ag(1/0.3)-TiN, since Ag plays a major role in antibacterial activity and Zn is auxiliary. But a large ratio of Ag not only impairs cells but also has a negative effect on antibacterial activity. In conclusion, Zn/Ag(1/0.3)-TiN offers both excellent cytocompatibility and antibacterial activity and has great potential in orthopedic implants.