Rapid, on-site and yes-or-no detection of Salmonella typhimurium in foods using Argonaute-enabled assay

Early detection and control of foodborne diseases are crucial for ensuring food safety and consumer health. Therefore, there is a need for faster and more sensitive detection methods. We developed a rapid, portable and visible lateral flow biosensor (LFB) for foodborne pathogenic bacteria detection powered by a Pyrococcus furiosus Argonaute nuclease (PfAgo), named as PfAgo-LFB. LAMP (Loop-mediated isothermal amplification) was used to amplify the target nucleic acid. By using PfAgo as the "lighting up" technology, we can overcome the limitations of false-positive results and lack of effective endpoint monitoring in LAMP, greatly enhancing its applicability. It turned out that PfAgo-LFB was able to provide yes-or-no (positive or negative) results with a limit of detection (LOD) as low as 1 CFU/mL for S. typhimurium and the detection range was between 100 to 108 CFU/mL. It was able to secure a sample-to-answer test for contaminated food samples in less than 45 min and demonstrated satisfactory selectivity. In summary, we designed a PfAgo-LFB that rendered a novel, rapid, accurate, easy-to-deploy, on-site and yes or no detection of S. typhimurium, which could be generalized for building a "one-for-all" biosensing platform.