Osteo-angiogenic and antibacterial activity of a multifunctional micro-porous coating on zirconium alloy

Despite the excellent mechanical properties and chemical stability of zirconium alloys, prosthesis loosening caused by biological inertness greatly hampered their application in implant materials. Therefore, the modification of bioactive elements to the alloy surface has been the topic of significant research. In this paper, we designed and prepared a Zn/Si/Cu-co-doped micro-porous coating (MAO-ZnSiCu) on the Zirconium alloy surface via micro-arc oxidation. The silicon-rich layer formed by SiO2 in this coating enhances the adhesion, spreading and proliferation of osteoblasts (OBs) and endothelial cells (ECs) in a considerable way. At the same time, the Si4+ and Cu2+ released from the coating stimulate the secretion of osteogenesis-related proteins and angiogenesis-related proteins, which have a synergistic impact on osteogenesis and angiogenesis. Moreover, Zn2+ show a synergistic effect with Cu2+ on destroying bacterial membranes, which resulting in obvious antibacterial ability at a low level of Zn2+ and Cu2+, and the cytotoxicity of high concentrations of ions could be avoided. In conclusion, the synergistic effect of Si, Zn, and Cu is comprehensively utilized in MAO-ZnSiCu coating, which has excellent osteo-angiogenic and antibacterial activities, and is a promising candidate for bone implant materials.