Improved in vitro and in vivo biocompatibility of dual plasma modified titanium alloy

Dual carbon and nitrogen (C–N) plasma immersion ion implantation (PIII) is conducted to modify Ti–6Al–4V alloy. A graded implanted layer containing TiN and TiC is formed and in comparison with the C-implanted and un-implanted sample, the C–N implanted sample exhibits improved surface roughness and in vitro cell adhesion and proliferation. Micro-CT evaluation conducted after 1, 6, and 12 weeks of implantation shows the least amount of average bone volume on the un-implanted Ti pin, whereas that on the C–N implanted sample is more than that on the C-implanted at every time point. The biocompatibility enhancement after dual C–N PIII is attributed to the synergistic effects rendered by TiN and TiC as well as altered surface roughness. Our results suggest that dual C and N PIII is the preferred technique for Ti–6Al–4V alloy in clinical applications.