Synergistic antibacterial effect of multifunctional TiO2_X-based nanoplatform loading arginine and polydopamine for promoting infected wounds healing

The gas therapy of some endogenous signaling molecules to treat diseases has caused extensive research, among which NO gas has shown great potential in fighting infection with various pathogens, promoting wound healing, etc. Here, we propose a photothermal/photodynamic/NO synergistic antibacterial nanoplatform by loading Larginine (LA) on mesoporous TiO2 and then encapsulating it with polydopamine. The obtained TiO2_x-LA@PDA nanocomposite possesses both the excellent photothermal effect and ROS generation ability of mesoporous TiO2, and the release of nitric oxide (NO) from L-arginine under near-infrared (NIR) light irradiation, while the sealing layer of PDA could induce NIR-triggered NO controlled release. In vitro antibacterial experiments confirmed that the synergistic effect of TiO2_x-LA@PDA nanocomposites has excellent antibacterial effects against Gramnegative and Gram-positive bacteria, while in vivo experiments showed that it has lower toxicity. It is worth noting that compared with the pure photothermal effect and ROS, the generated NO showed a better bactericidal effect, and NO had a better ability to promote wound healing. In conclusion, the developed TiO2_x-LA@PDA nanoplatform can be used as a nanoantibacterial agent, which can be further explored in the related biomedical field of photothermal activation of multimodal combined antibacterial therapy.

Automated summary

A photothermal/photodynamic/NO synergistic antibacterial nanoplatform was proposed by loading L-arginine (LA) on mesoporous TiO2 and encapsulating it with polydopamine. The obtained TiO2_x-LA@PDA nanocomposite exhibited excellent antibacterial effects against various bacteria, along with the ability to generate nitric oxide (NO) under near-infrared (NIR) light irradiation. The developed nanoplatform can be further explored in the biomedical field of photothermal activation of multimodal combined antibacterial therapy.