A highly sensitive colorimetric platform based on tricoordinate metal MOFs nanoenzymes and  smartphone RGB–assisted analysis for visualized detection of Salmonella typhimurium

This study presents a signal-amplified detection platform integrating magnetic separation, PtAuRu@PCN-224 nano-enzyme catalysis magnification, and smartphone RGB analysis. The developed detection system has the following advantages: ultra-high sensitivity, the detection limit in ultraviolet-visible light mode is 1 CFU/mL; it features rapid response and excellent selectivity, capable of distinguishing common foodborne pathogenic bacteria; the nanozyme exhibits excellent stability, with its activity remaining above 92% after being stored at 4℃ for 10 days; the recovery rates in four food samples were 98 to 103%; and the relative standard deviations were less than 3%. This platform combines the high catalytic performance of MOFs nano-enzymes with the convenience of RGB analysis on smartphones, providing a new solution for the detection of foodborne pathogens. Graphical abstract