A comparative biocompatibility analysis of ternary Nitinol alloys

Nitinol alloys are rapidly being utilized as the material of choice in a variety of applications in the medical industry. It has been used for self-expanding stents, graft support systems and various other devices for minimally invasive interventional procedures. However, the biocompatibility of this alloy remains a concern to many practitioners in the industry due to nickel sensitivity experienced by many patients. In recent times, several new Nitinol alloys have been introduced with the addition of a ternary element. Nevertheless, there is still a dearth of information concerning the biocompatibility and corrosion resistance of these alloys. This study compares the biocompatibility of several ternary Nitinol alloys and critically assesses the influence of the ternary element. ASTM potentiodynamic and potentiostatic in vitro corrosion tests are conducted to evaluate the corrosion resistance in biological media. The morphology of the alloys was examined using optical microscopy, SEM/EDS and Raman Spectroscopy. Based upon these studies, a comparative analysis of the growth of endothelial cells on each alloy is also presented.