Enhanced corrosion resistance and photothermal antibacterial properties of MAO/PCL-PDA/NG composite coating on Mg alloy

In this study, a composite coating of polycaprolactone layer and polydopamine-cyclodextrin (β-CD)/naringenin (NG) was prepared on the surface of a micro-arc oxidized (MAO) pretreated magnesium alloy by a two-step method. The findings demonstrate that the composite coating exhibits favorable corrosion resistance, biocompatibility, photo-thermal antimicrobial, and bone-enhancing characteristics. Compared with the MAO coating, the corrosion rate of the composite coating was significantly reduced from about 0.087 mm/y to 0.066 mm/y. The antimicrobial efficiency of the coating against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) under 808 nm laser irradiation was found to reach 93 % and 99 %, respectively. Furthermore, in vitro cytotoxicity assays, dead and live cell staining, and immunoblotting analysis showed that the coating exhibited favorable biocompatibility and osteogenic activity. This novel coating may have good application prospects in the treatment of osteoporosis-related fractures.