Cytocompatibility Evaluation of Ti-Ni and Ti-Mo-Al System Shape Memory Alloys

Abstract

Cytocompatibility of nickel-free Ti-Mo-Al shape memory alloys was evaluated and compared with that of a conventional Ti-Ni shape memory alloy. Two types of cytotoxicity tests were performed; in static and dynamic conditions. In the static condition, human normal diploid fibroblast HEL299 was cultured on the disks of the three materials and cell growth was examined. In the dynamic condition, the disks were rotated in extraction medium with zirconia balls at 37°C for 14 days, and the collected extraction medium was added into HEL299 culture to examine its inhibitive effect on cell growth. Quantification of metallic elements in the collected extraction medium was also performed. The results showed that Ti-Mo-Al alloys had a rate of cell growth similar to that of Ti-Ni alloy in the static condition. The extraction medium of Ti-Ni alloy, however, tended to inhibit cell proliferation more than those of Ti-Mo-Al alloys. Nickel was detected in all of these extraction media, but that of Ti-Ni alloy was about three times higher than those of Ti-Mo-Al alloys. These facts indicate that developed Ti-Mo-Al alloys have higher cytocompatibility than the Ti-Ni alloy.