Engineered manganese phosphate coatings on titanium implants: synergistic photothermal antibiosis and ion‐stimulated osteogenesis via zinc/calcium co‐doping

Abstract Titanium (Ti) implants are widely employed in orthopedic and dental applications due to their excellent mechanical strength and biocompatibility. However, poor osseointegration and implant‐associated infections (IAIs) remain major challenges. To tackle these issues, novel zinc (Zn)/calcium (Ca) co‐doped manganese phosphate (MnP) coatings were developed on Ti substrates via the phosphate chemical conversion (PCC) method. By adjusting the Zn and Ca concentrations, three distinct coatings—MnP, Zn 0.5 Ca–MnP, and Zn 2 Ca–MnP—were fabricated. These coatings exhibited controlled microstructures, transitioning from prismatic to packed lamellar crystals due to lattice distortion induced by Zn 2+ and Ca 2+ doping. This modification enhanced the bonding strength (26.04 ± 0.78 MPa) and corrosion resistance of the coatings. Notably, the Zn 2 Ca–MnP coating demonstrated near super hydrophilicity (contact angle: 7.5° ± 0.92°) and sustained ion release (Mn 2+ , Zn 2+ , and Ca 2+ ), promoting osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) while significantly upregulating osteogenic genes. Moreover, the coating achieved synergistic antibacterial efficacy (> 95% inhibition against Escherichia coli and Staphylococcus aureus ) through the combined effects of near‐infrared (NIR)‐induced photothermal heating and ion release. This dual‐functional approach, combining photothermal‐enhanced antibacterial activity with osteogenic promotion, offers a promising surface modification strategy for Ti implants in treating infectious bone defects.