Rapid Separation and Detection of Listeria Monocytogenes with the Combination of Phage Tail Fiber Protein and Vancomycin-Magnetic Nanozyme

In this work, a visual lateral flow assay for Listeria monocytogenes detection was developed based on dual-functional nanozyme probes with capture-catalytic activity combined with phage tail fiber protein (TFP). Vancomycin (Van), which exerted strong affinity towards Gram-positive bacteria, was modified on carboxylated Fe3O4 nanozyme with bovine serum albumin (BSA) as amplification carrier to specifically capture and separate pathogen. To improve the specificity for L. monocytogenes, TFP of phage was employed on test line as second recognition agent, which overcame non-specific binding of Van. Special color reaction between Coomassie Brilliant Blue and BSA was utilized as control zone to verify validity of test strip simply. Relying on enzyme-like catalytic activity of nanozyme, this biosensor realized colorimetric quantitative detection with a detection limit of 10 CFU mL-1. Analytic performance results suggested this nanozyme biosensor combined with recombinant TFP provided a portable, sensitive and specific strategy to detect L. monocytogenes and other bacteria.