Electrochemically deposited chitosan/Ag complex coatings on biomedical NiTi alloy for antibacterial application

Biomedical NiTi-based shape memory alloys suffer from post-surgery bacterial infection issues and it is of great importance to prevent bacteria adhesion and growth on the implants by using the proper surface modification techniques. In this study, a chitosan/Ag complex coating is deposited on NiTi alloy electrochemically to enhance the antibacterial characteristics. The composition and properties of the coatings are determined systematically. The thickness of the chitosan/Ag complex coating is around 7.5 μm and it adheres well to the NiTi substrate. The chemical state of silver in the chitosan/Ag complex coating is revealed to be different from that in deposited silver without chitosan by X-ray photoelectron spectroscopy (XPS) and leaching tests. Furthermore, the antibacterial properties of the chitosan/Ag complex coatings are assessed and there are significant effects against the model bacterial Escherichia coli (E. coli). The present study discloses that the complex antibacterial coating is promising in orthopedics, dentistry, and other biomedical applications.