Antibacterial Activity of Additive Manufactured NiTi Alloy Improved by Zinc Oxide-Doped DCPD-PCL Composite Coating

Laser power bed fusion (LPBF)-NiTi alloy is a promising medical implant material because it can form complex and precise structures. However, due to postoperative bacterial infection, it often leads to implantation failure, and its clinical application is limited. In this study, DCPD-PCL-ZnO composite coatings were fabricated on LPBF-NiTi alloy by electrodeposition and dip pulling. The influence of nano-ZnO doping content on the corrosion resistance, biocompatibility, and antibacterial properties of the composite coating was investigated. The con-sequences show that the DCPD-PCL-ZnO composite coating can effectively improve the corrosion resistance of LPBF-NiTi alloy. Especially when doped with 2 wt% nano-ZnO, the DCPD-PCL-ZnO composite coating shows excellent corrosion resistance, and the corrosion current (3.9 x 10-9 A/cm2) is about three orders of magnitude lower than that of bare alloy. A high cell survival rate was also demonstrated in cell experiments (101 %), indicating good biocompatibility. In addition, the composite coating has efficient antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), which can effectively reduce the risk of infection at the initial stage of implantation. Therefore, DCPD-PCL-ZnO composite coating LPBF-NiTi alloy has great clinical application potential.