Defect rich Zn-TiO2-x coating with NIR triggered bio-multifunctionality for combined anti-infection and enhanced osseointegration

The long-term clinical success of titanium-based implants is perpetually compromised by post-operative infection and suboptimal osseointegration. To address this dual challenge, we developed a defect-engineered, zinc-doped titania (Zn-TiO 2-x ) coating through a two-step process of micro-arc oxidation and subsequent alkaline reduction. This process endows the material with a profusion of oxygen vacancies (OVs), imparting significant absorbance in the near-infrared (NIR) spectrum. Upon 808 nm laser irradiation, this property translates into highly efficient photothermal conversion, which orchestrates a formidable, multi-modal antibacterial assault. The coatings exhibited exceptional bactericidal efficacy, achieving eradication rates of over 89% against S. aureus and 98% against E. coli . This potency stems from a synergistic trinity of hyperthermia via photothermal therapy (PTT), cytotoxic reactive oxygen species (ROS) generated through photodynamic therapy (PDT), and the intrinsic antimicrobial activity of released Zn 2+ . Concurrently, beyond antimicrobial prowess, the hierarchical porous microarchitecture acts in concert with the pro-osteogenic bioactivity of Zn 2+ to markedly enhance the adhesion, proliferation, and osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). This study presents a versatile coating strategy for endowing titanium implants with dual therapeutic capabilities, opening new avenues for smart implants that actively combat infection and promote tissue regeneration.