Photocatalytic Cu₂WS₄ Nanocrystals for Efficient Bacterial Killing and Biofilm Disruption

Bacterial biofilm-related wound infections threaten human health due to the lack of efficient treatments. Therefore, developing a novel strategy for wound infection care is urgently needed.

Cube-shaped Cu₂WS₄ nanocrystals (CWSNs) were successfully prepared via a microwave-assisted method. CWSNs, as photocatalysts, were first studied by using fluorescence spectroscopy for their ability to generate reactive oxygen species (ROS). The antibacterial and biofilm inhibition abilities of CWSNs were determined in vitro by using Staphylococcus aureus (S. aureus) as the model bacterium. Moreover, a CWSN gel was prepared and applied to treat S. aureus-infected wounds in mice. The toxicity of the CWSNs was evaluated through in vitro cell and in vivo animal experiments.

Studies on the properties of the CWSNs demonstrated that these nanomaterials can catalyze the generation of hydroxyl radicals (•OH) without the addition of H₂O₂ after visible-light irradiation, indicating their photocatalytic ability. Moreover, the in vitro experimental results showed that the CWSNs not only adhered to the surfaces of S. aureus to kill the bacteria, but also inhibited S. aureus biofilm formation. The in vivo study showed that the CWSN gel produced excellent antibacterial effects against S. aureus infected wounds in mice and effectively promoted wound healing. Furthermore, toxicity tests showed that the CWSNs have negligible toxicity in vitro and in vivo.

This work provides a potential photocatalytic antibacterial nanoagent for efficient bacterial killing, inhibition of biofilms growth and wound infection treatment.