In vitro and in vivo antibacterial activity of graphene oxide-modified porous TiO₂ coatings under 808-nm light irradiation

Bio-inertness and post-surgery infection on titanium (Ti) are the main causes of failure of biomedical implants in vivo. Near-infrared (NIR) photoactivated antibacterial therapy including photothermal and photodynamic therapies has attracted increasing attention due to the high bactericidal efficiency and little side effects. Although micro-arc oxidation (MAO) is an effective method to improve the biological activity of Ti implants, the porous TiO₂ coatings prepared by MAO do not respond to near-infrared (NIR) light to kill bacteria by the photothermal and photodynamic effects. In this work, graphene oxide (GO)-modified TiO₂ coatings (TiO₂/GO) are prepared on Ti to improve the photothermal and photodynamic ability of the MAO coatings. The TiO₂/GO coatings exhibit excellent antibacterial activity both in vitro and in vivo against Streptococcus mutans (S. mutans) under 808-nm NIR light irradiation due to the synergistic effects rendered by hyperthermia and reactive oxygen species (ROS). The NIR light-responsive antibacterial MAO coatings have large potential in combating implant-associated infections in clinical applications.