Two birds with one stone: A multi-functional nanoplatform for sensitive detection and real-time inactivation of pathogenic bacteria with NIR-triggered PTT/PDT

Given the increase in public safety incidents due to bacterial infections, sensitive detection and real-time inactivation of pathogenic bacteria have garnered increasing attention in the field of food safety, clinical diagnosis, and environmental monitoring. In this study, we constructed a "two-in-one" PB@DPA-Ce-GMP@Van (PCV) nanoplatform possessing enzyme-like properties and photothermal therapeutic (PTT) and photodynamic therapeutic (PDT) abilities for the detection and inactivation of pathogenic bacteria. PCV was captured on the surface of S. aureus to form a PCV/S. aureus complex. After centrifugation, PCV suspensions could catalyze non-fluorescent Amplex Red (AR) into fluorescent substrates and fluorescent scopolamine (SC) into non-fluorescent substrates. Hence, a ratiometric fluorescence probe with SC/AR reading was constructed for the sensitive detection of bacteria. The detection range reached 101–107 colony-forming unit (CFU)/mL, and the detection limit was as low as 5.0 CFU/mL. Furthermore, approximately 99.7 % of free S. aureus can be inactivated by the PTT and PDT abilities of PCV. Thus, this nanoplatform exhibits a novel advantage in detecting and inactivating bacteria. Moreover, the bacterial infection wound model indicated that PVC exerts good disinfection ability. This study is of immense significance in the application of targeted sensing, eliminating bacterial infection, and even clinical therapy.