Surface modification of NiTi alloy via a TiN coating functionalized with biomimic multilayer films

In this study, dextran sulfate (DS)/chitosan (CHI) multilayer films were fabricated on TiN-coated NiTi alloy to reduce Ni ion release and improve biocompatibility. The successful formation of TiN coating and DS/CHI multilayer films was demonstrated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Inductively coupled plasma mass spectrometry (ICP-MS) test showed that the Ni ion release from NiTi alloy significantly decreased after surface modification. Cytocompatibility including osteoblasts adhesion and differentiation function was evaluated in vitro. The results suggest that this surface modification process is beneficial for osteoblasts growth on NiTi alloy substrate. The approach presented here provides an attractive way for surface modification of NiTi alloy to meet the requirements of biomedical applications. (C) 2014 Elsevier B.V. All rights reserved.