Aptamer-DrivenMultifunctional Nanoplatform for Near-InfraredFluorescence Imaging and Rapid <i>In Situ</i> Inactivationof Salmonella typhimurium

Salmonella typhimurium (S. typhimurium) is a prominent pathogen responsible for intestinal infections, primarily transmitted through contaminated food and water. This underscores the critical need for precise and biocompatible technologies enabling early detection and intervention of bacterial colonization <i>in vivo</i>. Herein, a multifunctional nanoplatform (IR808-Au@ZIF-90-Apt) was designed, utilizing an S. typhimurium-specific aptamer to initiate cascade responses triggered by intracellular ATP and GSH. The nanoplatform precisely targets S. typhimurium<i>via</i> aptamer recognition, promoting bacterial aggregation through nanoparticle sedimentation in an oscillatory system. Furthermore, the intelligent nanoplatform significantly enhances the sensitivity of S. typhimurium detection based on near-infrared (NIR) fluorescence signals, achieving a detection limit as low as 2 CFU mL^–1. Additionally, <i>in situ</i> NIR irradiation was applied at the 30 min peak of fluorescence detection, enabling rapid and irreversible inactivation of S. typhimurium through the synergistic effects of photothermal and photodynamic effects. Importantly, in a mouse model of intestinal infection, the nanoplatform successfully detected early S. typhimurium colonization and achieved highly efficient <i>in situ</i> inactivation without adversely affecting the major organs. In conclusion, the nanoplatform achieved precise localized detection and <i>in situ</i> inactivation of S. typhimurium, offering valuable insights for disease surveillance and epidemiological studies, with promising implications for food safety and public health.