Manganese-driven microstructural evolution of calcium zinc phosphate coatings on titanium for enhanced photothermal antibacterial and osteogenic performance

• Manganese doping drives microstructural evolution of calcium zinc phosphate coatings into a dense bilayered nanostructure. • Manganese doping enhances wettability, bonding strength, and corrosion resistance. • Near-infrared photothermal effect combined with ion release enable antibacterial activity and promote osteogenesis. • A structure–property relationship is established to overcome the trade-off between infection control and osseointegration. Functionalizing titanium (Ti) implant surfaces to simultaneously prevent infection and promote osseointegration is a critical challenge. Conventional calcium zinc phosphate (CaZnP) coatings exhibit inherent trade-offs between antibacterial efficacy and osteogenic performance, while the role of manganese (Mn) in regulating coating microstructure and associated biological functions has not yet been systematically clarified. In this study, Mn-doped CaZnP coatings were fabricated on Ti via phosphate chemical conversion (PCC), and the coupling between Mn-induced microstructural evolution, physicochemical properties, and biological functions was comprehensively investigated. Mn doping induced pronounced grain refinement and phase reconstruction, driving the formation of a dense bilayered nanostructure. This hierarchical architecture resulted in improved surface wettability, enhanced interfacial bonding strength, and increased corrosion resistance. Under near-infrared (NIR) irradiation, the photothermal effect acted synergistically with the sustained release of antibacterial ions, resulting in highly effective bactericidal performance. In vitro experiments further demonstrated that Mn-doped coatings significantly promoted the adhesion, spreading, and proliferation of bone marrow mesenchymal stem cells (BMSCs), while markedly enhancing osteogenic differentiation. This study establishes a “structure–property-function” relationship governed by Mn-driven microstructural regulation and presents a mild, scalable surface modification strategy, providing new avenues for the rational design and clinical translation of multifunctional Ti implants.