TBA magnetically functionalized materials combined with biomass-derived fluorescent probe for Listeria monocytogenes detection in a sandwich-like strategy

Abstract

Ultrasensitive and simultaneous quantitative detection of Listeria monocytogenes (L. monocytogenes) that can survive in vacuum packaging and frozen food is critical to public health. Herein, teamed boronate affinity (TBA) magnetically functionalized materials combined with biomass fluorescent probe for L. monocytogenes detection in a sandwich-like strategy was established. Firstly, we prepared new TBA magnetically functionalized materials by reducing the pKa value of phenylboronic acid through the TBA strategy in the form of self-assembled intermolecular B-N coordination bonding. To our knowledge, this is the first study where TBA magnetically functionalized materials were utilized for the identification and capture of bacteria, with a high capture efficiency of over 90.8% in spiked lettuce samples for L. monocytogenes (within 35 min), showing superior capture ability. Then, Anti-L. monocytogenes monoclonal antibody was labeled in biomass-derived fluorescent probe with the help of biotin-streptavidin system to achieve specific and sensitive detection of L. monocytogenes. The sandwich-like strategy shows high sensitivity of designed fluorescence sensing platform for L. monocytogenes with a wide linear range (2.2 × 101–2.2 × 106 CFU/mL), a low limit of detection (2.2 × 101 CFU/mL), and a satisfactory recovery rate (85.19%–106.69%) spiked lettuce sample. Notably, the method was low-cost, general and had strong application prospects in the field of food safety.