Fe modified Ca-Mg-P coating with synergistic antibacterial, photothermal and osteogenic properties on magnesium alloys

The overly rapid degradation rate and uneven corrosion remain the main obstacles restricting the application of bio-magnesium alloys. Owing to their excellent biocompatibility and corrosion resistance, phosphate coatings are being increasingly applied to the surfaces of biomedical magnesium alloys. Bacterial infection is another key factor leading to the failure of implant surgery. Since phosphate itself does not have antibacterial properties, its clinical use is limited. In this work, the Ca-Mg-P coating was modified by Fe ion implantation through the MEVVA technology. Surprisingly, after Fe ion implantation, not only the antibacterial and corrosion-resistance properties of the Ca-Mg-P phosphate coating were enhanced, but also its photothermal conversion performance was improved. This enables the new Ca-Mg-P/Fe phosphate composite coating to possess both ionic antibacterial and photothermal antibacterial properties simultaneously. The composition mechanism, corrosion resistance, photothermal properties and bio-compatibility of the Ca-Mg-P/Fe phosphate composite coating were systematically studied. The distribution of injected ions and energy loss were simulated using the Monte Carlo method, and the corrosion-resistance mechanism of the Ca-Mg-P/Fe phosphate coating was explained by first-principles calculations.