Single NIR laser-triggered multifunctional composite hydrogel for bacterial detection and photothermal/photodynamic synergistic sterilization

Rapid monitoring and effective elimination of pathogenic bacteria in the environment are crucial for ensuring public health and safety. However, designing an integrated platform with both rapid detection and sterilization capabilities remains challenging. Herein, multifunctional hydrogel (NH 2 -NM@IR780/OSA/MBG hydrogel) triggered by a single NIR laser was constructed for rapid detection and synergistic photothermal/photodynamic sterilization. The NH 2 -NM@IR780/OSA/MBG hydrogel was prepared via a Schiff base reaction between NH 2 -NM@IR780 and oxidized sodium alginate (OSA), followed by the incorporation of 4-methylumbelliferyl beta-D-glucuronide (MBG). In vitro experiments demonstrated that the hydrogel responds to enzymes secreted by bacteria to generate blue fluorescence, achieving rapid detection of bacteria. Meanwhile, IR780 in NH 2 -NM@IR780 hydrogel under 808 nm laser irradiation not only generated abundant reactive oxygen species (ROS) for photodynamic therapy, but also produced a large amount of heat to kill bacteria. Through the above process, a single NIR could simultaneously regulate the photodynamic and photothermal performance to achieve efficient sterilization, which effectively improved the synergistic effect between the two therapeutic modes. Therefore, our strategy provides a novel way to achieve rapid bacterial detection and efficient sterilization. Graphical abstract