A “sense-and-treat” hydrogel for rapid diagnose and photothermal therapy of bacterial infection

[Display omitted] •The two functional components enhanced the crosslinking density of the hydrogel.•The hydrogel had excellent photothermal effect.•The hydrogel had the responsiveness of pH to visually perceive color changes.•The hydrogel allowed real-time observation of wound healing with the naked eye. Rapid diagnosis and effective killing of pathogenic bacteria causing epidemics is an important assignment for the prevention of human health threats worldwide. Herein, we propose the pH susceptible bromothymol blue (BTB) and near-infrared (NIR) effect copper catechol (CuCL) nanosheets into carrageenan polysaccharide hydrogels to realize a system integrating sensing and sterilization. In this system, BTB is used as an intelligent pH indicator for the naked-eye diagnosis of bacterial infection, showing visible color changes. After diagnosis, CuCL nanosheets-based photothermal therapy (PTT) is used to treat and kill bacteria. In addition, a light-responsive, “colorimetric band-aid” hydrogel platform is also proposed for real-time monitoring of MRSA-infected wound healing process in vivo. Overall, our work would not only boost the exploitation of promising photothermal catalysts, but also provide new insights for the development of intelligent and simple platform for bacterial infection diagnosis and treatment.