Nickel–titanium alloy: Cytotoxicity evaluation on microorganism culture

High purity nickel (Ni) and titanium (Ti) targets have been used to form well-defined thin films of nitinol on Ti substrate by pulsed laser deposition (PLD) technique. Their chemical composition, crystalline structure and surface properties have been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). We have shown that by varying the deposition parameters such as laser fluence and number of laser pulses, we are able to control the film thickness as well as film’s uniformity and roughness. Cytocompatibility tests have been performed through in vitro assays using microorganisms culture cells such as yeasts (Saccharomyces cerevisiae) and bacteria (Escherichia coli), in order to determine the thin film’s toxic potential at the in vitro cellular level. Microorganism’s adhesion on the nitinol surface was observed and the biofilm formation has been analyzed and quantified. Our results have shown no reactivity detected in cell culture exposed to NiTi films in comparison with the negative controls and a low adherence of the microorganisms on the nitinol surface that is an important factor for biofilm prevention. We can, therefore, conclude that NiTi is a good candidate material to be used for implants and medical devices