In situ growth of Zn-MOFs coating on magnesium implants induced by graphene oxide with synergistic antibacterial, osteogenic, and self-healing properties

Magnesium implants show great promise for treating bone disorders, yet face challenges of rapid corrosion and inadequate biological functionality. The in-situ grown ZIF-8 coating enhances corrosion resistance of magnesium implants by improving interfacial adhesion while achieving biocompatibility and antibacterial activity through Zn²⁺ release. Meanwhile, defects on the surface of graphene oxide (GO) adsorb Zn²⁺, triggering the heteroepitaxial growth of ZIF-8 nanoparticles. In this study, a composite coating of GO-doped layered double hydroxides (LDHs) on magnesium alloy micro-arc oxidation (MAO) coating surface was used as the substrate, with zinc phytate (Zn-IP6) as the zinc source, successfully inducing the in situ growth of ZIF-8 coating (ZP/GLDHs coating). The self-healing ZP/GLDHs coating markedly promoted adhesion, spreading, and proliferation of L929 fibroblasts and osteoblasts on its surface. In photothermal antibacterial assays against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), it achieved 98.5% and 94.4% bacterial reduction, respectively. This study presents a novel strategy for the design of multifunctional magnesium implants that integrate antibacterial, osteogenic, and self-healing capabilities.