Based on the synergistic effect of Mg2+ and antibacterial peptides to improve the corrosion resistance, antibacterial ability and osteogenic activity of magnesium-based degradable metals

Abstract

To overcome the restricted degradation, poor antiacterial and osteoindctive problems of magnesium and its alloys, this study presented the spinning coating of an antimicrobial peptide (AP)-loaded silk fibroin (SF) composite onto a corrosion-resistant MgO-coated AZ31 Mg alloy via anodization (aMgO) and electrodeposition (eMgO) methods. The composite coatings not only created a smooth and hydrophilic surface, but also obviously improved the corrosion resistance according to the test of corrosion potential and current density. The colonization of E. coli on MgO–AP composite coatings was significantly reduced as compared to the MgO layers, due to the potential synergetic effects of APs and Mg²⁺. Compared with the bare AZ31, the composite coating inhibited the corrosion of the substrate and the release of Mg²⁺, supported the adhesion, spreading and proliferation of osteoblasts, and presented a significantly improved osteogenic differentiation trend. Therefore, the MgO–AP composite coating, which had both antibacterial and bone-promoting abilities, was expected to be applied for surface modification of magnesium alloy implants to solve the clinical problems of bacterial infection and poor osseointegration.