Effect of berberine-loaded ultrasonic micro-arc oxidation coating on the antibacterial performance and cytocompatibility of biomedical magnesium alloys

To enhance the antimicrobial properties and cytocompatibility of a pure magnesium alloy, the alloy was subjected to ultrasonic micro-arc oxidation (UMAO) treatment loaded with berberine. The antibacterial activity and cytocompatibility of the magnesium alloy before and after the berberine-loaded UMAO coating treatment were investigated using plate counting, CCK-8 assays, and scanning electron microscopy (SEM) to evaluate the application potential of this composite coating as a surface bio-modification method for magnesium alloys. Surface microstructural characterization indicated that the coating had successfully incorporated the bioactive component. Plate count results showed that the berberine-loaded UMAO-coated magnesium alloy still exhibited strong antibacterial activity (≥96%) against Escherichia coli and Staphylococcus aureus, indicating that the berberine-loaded UMAO coating endows the magnesium alloy with long-term antibacterial performance. cytocompatibility evaluation results showed that the berberine-loaded UMAO treatment did not induce cytotoxicity; rather, it improved the early adhesion of MC3T3-E1 cells and promoted the expression of BMP-2 and TGF-β, providing important evidence for the development of a new generation of multifunctional magnesium-based implants.