A hierarchical micro/nanostructural coating loaded ZIF-8@RIS on Ti implants for NIR responsive antibacterial at mild temperature

Titanium (Ti)-based biomedical implants are frequently associated with complications such as aseptic loosening and bacterial infection, both of which substantially reduce the overall success rate of implantation. In this study, a composite coating, consisting in ZIF-8, created through the coordination of zin ions (Zn²⁺) with 2-methylimidazole, loaded with risedronate sodium (HT/ZIF-8@RIS), was fabricated on pure Ti surfaces, using a two-step alkaline hydrothermal method. This coating simultaneously conferred antibacterial properties and enhanced osteogenic differentiation. Experimental results demonstrated that the HT/ZIF-8@RIS coating exhibited excellent photothermal antibacterial performance, effectively inhibiting bacterial biofilm formation at a mild temperature of ~50 °C. In vitro and in vivo experiments revealed that the HT/ZIF-8@RIS coating possessed good biocompatibility, and as-prepared coatings can be promising for osseointegration as the proliferation and differentiation of osteoblasts was significantly promoted in vitro. Further animal experiments confirmed that the implants with the HT/ZIF-8@RIS coating exhibited superior photothermal antibacterial properties without damaging surrounding tissues. The overall findings of this study offer an effective and promising strategy for improving the antibacterial efficacy and performance of Ti-based implants in clinical settings.