Mechanical Properties and in Vitro and in Vivo Biocompatibility of a-C/a-C:Ti Nanomultilayer Films on Ti6Al4V Alloy as Medical Implants.

Hydrogen-free a-C/a-C:Ti nanomultilayer films are deposited on medical Ti6Al4V alloy using a closed field unbalanced magnetron sputtering under graded bias voltage. The mechanical and tribological properties of the nanomultilayer films are performed on the nanoindentor, Rockwell and scratch tests, and ball-on-disk tribometer. The biological properties are evaluated by cell cytotoxicity, genotoxicity, subchronic systemic toxicity and implant. The hard a-C/a-C:Ti nanomultilayer films on medical alloy exhibit high adhesion strength and excellent tribological properties in both ambient air and Hank's solution. Biocompatibility results reveal the film no cytotoxity, no genotoxicity, no subchronic systemic toxicity and no contraindications in implant systems. Because of excellent mechanical properties and biosafety, the carbon-based films on medical alloy unveils a prospective application in medical implants.