Construction of Chitosan-Coated TiO2/In2S3 Heterojunction on Ti surfaces for NIR Triggered Photothermal/photodynamic Synergistic Enhanced Antibacterial

In 2 S 3 forms a Z-scheme heterojunction with TiO 2 , broadening the light response range, improving ROS generation. • Photothermal-photodynamic synergy reduces the required photothermal temperature. • The TiO 2 / In 2 S 3 /Chitosan composite coating exhibits enhanced antibacterial activity. • The composite coating exhibits excellent biocompatibility. Implant-associated bacterial infections remain a major challenge in orthopedic and dental applications, often compromising implant integration and longevity. For this reason, the synergistic antibacterial strategy of photothermal and photocatalysis has become one of the important methods in the field of antibacterial. To synthesize high-efficiency near-infrared (NIR) light-responsive catalysts, a titanium oxide/indium sulfide (TiO 2 /In 2 S 3 ) heterojunction antibacterial coating was prepared on the titanium-based surface using anodic oxidation and wet chemical deposition methods. Compared with titanium alloy, the TiO 2 /In 2 S 3 heterojunction showed a suitable energy band structure, improved light absorption, and enhanced carrier separation capability, thus enhancing photothermal catalytic activity and promoting the production of bacterial reactive oxygen species under NIR light. Indeed, the TiO 2 /In 2 S 3 heterojunction narrowed the bandgap (~2.5 eV) and efficiently generated reactive oxygen species (•O₂⁻ and •OH) under NIR irradiation. Furthermore, the successful deposition of chitosan (CS) endowed the TiO 2 /In 2 S 3 heterojunction with osteogenic activity, promoting the proliferation and differentiation of osteoblasts. In vitro , results demonstrated effective antibacterial performance against Escherichia coli and S taphylococcus. aureus , inhibited biofilm formation, and supported collagen secretion and mineralization. In vivo , NIR irradiation raised the implant site temperature to below 50   °C, enabling safe and efficient sterilization, and showing no organ toxicity. These results highlight CS-coated TiO 2 /In 2 S 3 heterojunction as a promising multifunctional coating that combines infection control with osteogenic support, providing a potential strategy for improving the safety and longevity of titanium-based implants. Download: Download high-res image (156KB) Download: Download full-size image