Preparation and antibacterial properties of ZnSr-doped micro-arc oxidation coatings on titanium

Titanium and titanium alloys are biologically inert materials. The lack of rapid osseointegration and resistance to bacterial infection remain unsolved problems for these materials. To overcome these problems, zinc (Zn) and strontium (Sr) at different concentrations were doped into the surface coating of implants by one-step micro-arc oxidation (MAO) technology. The microstructure, elemental content, chemical composition and corrosion resistance of the coating were studied. The antibacterial activity and biocompatibility of the coating were evaluated by antibacterial tests and proliferation tests of bone marrow mesenchymal stem cells (BMSCs). The results show that the coating is mainly composed of the rutile phase and anatase phase. The content of zinc in the coating decreases with increasing strontium concentration. The addition of zinc and strontium in the electrolyte does not significantly change the microstructure and physical and chemical properties of the coating. The ZnSr-TiO2 coating shows good antibacterial activity against Staphylococcus aureus and Porphyromonas gingivalis, which can effectively promote the proliferation and differentiation of bone marrow mesenchymal stem cells (BMSCs), and the cells on the coating with a higher strontium content exhibit greater proliferation.