Phage@lanthanide metal-organic framework-based fluorescent biosensor for smartphone-assisted simultaneous detection of multiple foodborne pathogens

The simple, rapid, and simultaneous detection of multiple foodborne pathogens in food is crucial for ensuring public safety. In this study, a rational design strategy for lanthanide-based metal-organic frameworks (Ln-MOFs), informed by theoretical calculations, was proposed. The calculated results were experimentally verified to screen out the optimal Ln-MOF for fluorescence efficiency. The selected Ln-MOFs were coupled with phages that exhibit specific pathogen recognition to develop phage@Ln-MOF fluorescent probes, while the magnetic nanoparticles were conjugated with phages to form capture probes. On this basis, a fluorescent biosensor was developed for the simultaneous detection of three major foodborne pathogens-Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Salmonella. This sensor facilitated the detection of all three pathogens within 15 min, with limit of detection (LOD) as low as 1 CFU/mL. Moreover, this fluorescent biosensor was compatible with on-site visual detection, utilizing a self-designed portable dark box and smartphone-assisted visualization, achieving an LOD of approximately 1-2 CFU/mL for E. coli, S. aureus, and Salmonella. This work demonstrates a novel approach for the rapid on-site detection of multiple foodborne pathogens, which holds promise for advancing field-ready diagnostic tools in food safety monitoring.