One-step fabrication of Ag@Polydopamine film modified NiTi alloy with strong antibacterial property and enhanced anticorrosion performance

NiTi alloy has a great potentials for practical applications in medical field. Despite the full sterility and preoperative antibiotic prophylaxis, postoperative infection induced by NiTi implants occurs frequently, which could result in delayed healing, implant failure, and other post-surgical complications. In addition, approximately 50% of Ni in NiTi alloys is of considerable concern due to the adverse symptoms caused by the excessive Ni exposure in the human issues. Designing Ag/Pdop composite film on the surface of NiTi may improve its antibacterial activity and inhibit the Ni ions release. However, the synthesis might be constrained by the manufacture procedures which involve multiple steps and require a long time. In our study, Ag@Pdop hybrid films were designed to modify the surface of NiTi alloys by taking a one-step immersing approach. The formation of the Ag@Pdop could undergo a co-deposition of a fast formation of Ag NPs and a time-consuming formation of Pdop films on the NiTi surface. Especially, the 40Ag@Pdop modified NiTi achieved strong antibacterial performance, better anticorrosion behavior, sustainable release of Ag ions, and desirable cytocompatibility. In addition, the leaching of Ni ions from the NiTi alloys can be effected prevented by the 40Ag@Pdop hybrid film.