Bone regeneration and antibacterial properties of calcium-phosphorus coatings induced by gentamicin-loaded polydopamine on magnesium alloys

Improving the corrosion resistance, osteogenic activity, and antimicrobial capacity of the magnesium-based implant is considered the key to promoting their large-scale clinical application. In this study, we reported a novel calcium-phosphorus coating induced by gentamicin (G)-loaded polydopamine for the surface treatment of the magnesium alloy. According to material characterization, immersion tests, and electrochemical analysis, the composite coating has a dense structure and a high crystallinity for greater corrosion resistance. Meanwhile, drug release and antimicrobial experiments demonstrated that the magnesium matrix loaded with gentamicin showed strong inhibition of Escherichia coli and Staphylococcus aureus, and the calcium-phosphorus coating further prolonged the release profile of G, which would contribute to the long-term bactericidal activity of the magnesium implants. In addition, the coating significantly promoted the adhesion, proliferation, and osteogenic differentiation ability of MC3T3-E1. The results of in vivo experiments confirmed that magnesium alloys with composite coatings significantly promoted bone regeneration under infected conditions. This study provides a promising strategy for the development of multifunctional magnesium-based implants with good corrosion resistance, and antibacterial and osteogenic capabilities.