Hybrid TiO2/AgNPs/g-C3N4 nanocomposite coatings on TC4 titanium alloy for enhanced synergistic antibacterial effect under full spectrum light

The hybrid TiO2/AgNPs/g-C3N4 nanocomposite coatings were constructed on TC4 alloy by a hydrothermal and calcining method. TiO2/AgNPs/g-C3N4 nanocomposite coatings demonstrated excellent biocompatibility and osteogenesis compared to those of titanium alloy. The existence of trace AgNPs on the surface and interface of the heterojunction could further enhance the transfer and separation of photogenerated electron/hole pairs, which greatly improved the antibacterial performance under full spectrum light. Holes at the valence band of TiO2 and g-C3N4 reacted with adsorbed H2O to generate •OH, killing bacteria through photocatalytic redox reaction under light irradiation, while released AgNPs exhibited bacteriostatic efficacy with or without light. This study provides a pathway of coating modification for further improving the antibacterial properties of heterojunction coatings and maintaining the biocompatibility of matrix materials.