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

In this paper, silver nanoparticles (Ag NPs) containing polydopamine (Pdop) films (Ag@Pdop hybrid films) was designed to modify the surface of nickel-titanium (NiTi) alloys by taking a one-step immersing approach. The formation of the Ag@Pdop hybrid films could undergo a co-deposition of a fast formation of Ag NPs and a time-consuming formation of Pdop films on the NiTi surface. The loading content of Ag NPs could be controlled by making adjustment to the initial concentration of AgNO₃ (C_AgNO3). In such films, the endowed antibacterial and enhanced anticorrosion properties of the Ag@Pdop modified NiTi alloys are mainly attributed to Ag NPs and the Pdop film, respectively. Compared with the polished NiTi, the obtained 40Ag@Pdop hybrid film exhibits strong antibacterial performance (antibacterial ratio > 99%), improved corrosion resistance property, and desirable cytocompatibility. Additionally, the film can effectively inhibit the Ni ions leaching from the substrate and display a sustainable release of Ag ions. This work could provide an effective guidance on the design of Ag containing films to prevent the infection induced by implantation.