Effect of strontium doping concentration on the degradation behaviour and cytocompatibility of micro‑arc oxidation coated magnesium alloy

Magnesium alloys show promise for oral guided bone regeneration (GBR) membranes, but their corrosion resistance needs improvement. Micro-arc oxidation (MAO) enhances corrosion resistance, yet the micropores in the MAO coating reduce its protective effect. In this work, strontium (Sr) – with osteogenic-promoting and pore-sealing properties – was incorporated into the coating. The effects of different Sr concentrations on corrosion resistance and cytotoxicity were investigated. The results showed that at 1 g/L Sr, the Sr-phosphorus compounds effectively sealed the micropores. However, higher Sr contents deteriorated the degree of film formation, causing micropore aggregation and micro-cracks, which lowered the corrosion resistance. Sr incorporation improved the cytocompatibility; at 1 and 3 g/L, the cell proliferation rates exceeded 90%. In conclusion, the samples prepared with 1 g/L Sr exhibit the most promising application prospects.