Preparation and Characterization of Corrosion-Resistant MgF2-PDA-EGCG Coatings on AZ31B Magnesium Alloy with Antibacterial and Osteoinductive Properties

Bone defect repair relies on the reconstruction of the maxilla and alveolar bone. Magnesium and its alloys offer great potential as implant materials due to their biocompatibility and mechanical properties, but their rapid degradation limits clinical use. This study developed an MgF 2 -polydopamine-Epigallocatechin gallate (MgF 2 -PDA-EGCG) composite coating on AZ31B magnesium alloy using hydrofluoric acid fluorination and layer-by-layer self-assembly. The coating’s corrosion resistance, biocompatibility, antibacterial properties, and osteogenic potential were evaluated. Characterization showed a dense, uniform coating (∼5.6 ± 0.2 μm thick) that significantly improved corrosion resistance. In a seven-day hydrogen evolution test and long-term immersion study, the P2E0.5 coating reduced hydrogen release (0.57 ± 0.16 mL/cm 2 ) and mass loss (7.31 ± 0.83%). Biocompatibility tests (CCK-8 and live/dead staining) confirmed no cytotoxicity. Antibacterial tests showed inhibition rates of 75.8% for Escherichia coli and 83.43% for Staphylococcus aureus. ALP activity was 188.18% ± 37.56% of the control, indicating enhanced early osteogenesis. In summary, the MgF 2 -PDA-EGCG coating improves the corrosion resistance and biological properties of AZ31B magnesium alloy, supporting its potential for biomedical implants.