Study of antimicrobial effects and adherence of nitinol: a comparison between thin film and bulk form

Nickel-titanium (nitinol) can be used in various biomedical prosthetic devices. Microorganism adhesion properties of nitinol may be decreased by oxidizing agents and surface heat treatment. In this study, we compared the microorganism adhesion and cytotoxic effects of the thin film and bulk form of nitinol. In this analytical comparative study, thin film and bulk forms of nitinol were treated by microorganism suspension in different culture flasks. Adherence activity of these forms was studied by electron microscopy. The number of microorganisms was counted before and after adoption to the surface of alloy. On the thin film, a decrease rate of 14% for Ecoli, 44% for P.aeroginosia, 30.1%for S.aureus, 22% for B.cereus and 6.4% for C.albicans were noticed. In the bulk form, decrease rate of cells were 39% for E.coli, 62% for P.aeroginosa, 61.9% for S.aureus, 49% for B.cereus and 31% for C.albicans. There found lower decrease rate of cells of thin film compared with the bulk form (mean decrease rate of 39% for thin film and 62% for bulk form; P value<0.05). The thin film of nitinol has less cytotoxic effects in comparison with the bulk form. The lower adherence activity of the thin film can be attributed to smoothness and better biocompatibility of the thin film. This may be a promising alloy for development of medical prosthetic devices.