Closed‐Loop Monitoring of Pathogenic Bacteria with a Pt Single Atom@Quinone–Phenol Nanozymes‐Based Platform: Enables Accurate Pathogen Detection and Eradication

ABSTRACT The integration of accurate detection and immediate bactericidal in a single platform significantly enhances pathogen monitoring and control capabilities, but nanomaterial functional compatibility remains a major challenge. Here, we developed a multifunctional nanoplatform integrating multimode flexible detection and magnetic aggregation‐induced sterilization by utilizing the synergistic effect of quinone–phenol grafting nanozymes loaded with Pt single atoms (Pt SA@Q‐ACDs) and magnetic carbon dots (Fe 3 O 4 @DCDs). In Pt SA@Q‐ACDs, Pt SA increased the electron transfer from the quinone–phenol system, and the hydroxyl and pyridine state N defects sequentially synergized to form a double anchor site, the energy barrier for reducing H 2 O 2 was reduced, constituting a “1 + 1 > 2” bicatalytic system, which improved signal output and sterilization efficiency. Fe 3 O 4 @DCD enriches target bacteria through magnetic induction, dramatically reduces background interference, and increases the sterilization efficiency to 100% while realizing the detection of pathogenic bacteria at the single‐cell level. Complementing this, we designed an intelligent portable device capable of dynamically switching and interpreting multimodal signals, enabling adaptable field deployment. The multifunctional platform can realize early warning from food processing to the terminal, combined with high bactericidal efficiency, and can implement “closed‐loop monitoring” for pathogenic bacteria in an all‐round way, which has great potential.