Enhancing the cell proliferation performance of NiTi substrate by laser diffusion nitriding

� 2016 Elsevier B.V. Nickel-titanium (NiTi) shape memory alloy is one of the popular implant materials in orthopaedic applications due to its special mechanical properties. However, the presence of Ni has raised safety concerns and hence limited its applications. In the present study, this issue was addressed through laser diffusion nitriding on NiTi to form TiN coating on the surface. Optimum laser parameters to produce desirable surface without changing the surface topography of NiTi substrate were determined. This paper detailed the nitriding of NiTi by fiber laser for enhancing the hydrophilicity and biological performance. The laser treated surfaces were characterized by scanning-electron microscopy (SEM) and X-ray diffraction (XRD). The wettability and cell viability performance were studied using contact angle measurement and MTT assay. The results demonstrated that an optimized laser treated surface could lead to improvements in biocompatibility of NiTi.