Balancing the Anti-Bacterial and Pro-Osteogenic Properties of Ti-Based Implants by Partial Conversion of ZnO Nanorods into Hybrid Zinc Phosphate Nanostructures

Bacterial infection and inferior osseointegration are major complications associated with titanium (Ti) based implants. Although surface-engineered zinc oxide (ZnO) nanorods exhibit remarkable antibacterial ability, their potential biomedical applications are hampered by their pronounced cytotoxicity. Herein, inspired by the in vivo degradation process of znic, ZnO nanorods are converted into thermodynamically more stable zinc phosphate (Zn3(PO4)2 ?through a simple hydrothermal treatment in a hydrogen phosphate solution. By adjusting the conversion ratio, the surface morphology, release of zinc ions (Zn2+), and generation of reactive oxygen species can be finely tailored to overcome the cytotoxicity of ZnO nanorods while preserving their antibacterial capability. Furthermore, an optimized amount of Zn2+ released from the ZnO/Zn3(PO4)2 hybrid coating enhances osteogenic differentiation and extracellular matrix mineralization of human bone marrow mesenchymal stem cells by reprogramming their metabolic configuration. An implant-related infection model in rabbit femurs indicates that the hybrid ZnO/Zn3(PO4)2 coating can even promote osseointegration in the presence of pathogenic bacteria. This surface modification strategy which endows Ti-based implants with superior anti-bacterial and pro-osteogenic properties holds great clinical potential for orthopedic and dental applications. ZnO/Zn3(PO4)2 hybrid coating is prepared through a simple hydrothermal treatment of ZnO nanorods in a hydrogen phosphate solution. By adjusting the conversion ratio, the cytotoxicity of ZnO nanorods is overcome while their antibacterial capability is preserved. Furthermore, an optimal release of Zn2+ from ZnO/Zn3(PO4)2 hybrid coating enhances osteogenic differentiation and extracellular matrix mineralization of stem cells by reprogramming their metabolic configuration.image