Universal Nanoplatform for Ultrasensitive Ratiometric Fluorescence Detection and Highly Efficient Photothermal...

Pathogenic bacterial contamination in diverse environments seriously threatens human health. One of the most valuable approaches is to effectively combine sensitive detection with efficient sterilization to achieve source control of pathogens. Here, we constructed a nanoplatform of Bi₂S₃@MnO₂@Van with targeting, photothermal, and oxidase properties for the detection and on-demand inactivation of bacteria. The Bi₂S₃@MnO₂@Van nanorods (NRs) can be trapped on the surface of Gram-positive bacteria such as Staphylococcus aureus, forming a complex of Bi₂S₃@MnO₂@Van/S. aureus. After being centrifuged, the suspension of Bi₂S₃@MnO₂@Van NRs can catalyze the non-fluorescent Amplex Red (AR) into a fluorescent substrate and fluorescent Scopoletin (SC) into a non-fluorescent substrate. Thus, a ratiometric fluorescent sensor was constructed for the sensitive detection of bacteria with the fluorescent intensity ratio (SC/AR) as a readout, which improves anti-interference capability and can be used in real sample detection. The detection limit reaches as low as 6.0 CFU/mL. Meanwhile, the sediment contains Bi₂S₃@MnO₂@Van/S. aureus where the bacteria can be effectively inactivated, thanks to the excellent photothermal property of Bi₂S₃@MnO₂@Van NRs under near-infrared irradiation. The antibacterial efficiency reaches as high as 99.1%. The investigation provides an effective way for sensitive detection and highly efficient killing of pathogenic bacteria with a universal platform.