Dual recognition and highly sensitive detection of Listeria monocytogenes in food by fluorescence enhancement effect based on Fe3O4@ZIF-8-aptamer

Abstract

A highly sensitive and selective foodborne pathogen detection system is essential to ensure food quality and public health. Therefore, in this study, a dual recognition and highly sensitive detection of Listeria monocytogenes by fluorescence enhancement strategy based on Fe₃O₄ @ZIF-8 have been developed. Aptamer absorbed on Fe₃O₄ @ZIF-8 were used for the specific capture of Listeria monocytogenes, and the conjugates of anti-Listeria monocytogenes antibody-biotin and streptavidin-FITC were used as signal amplification and fluorescence recognition probes binding with target bacteria. Simultaneously, the quantitative detection of Listeria monocytogenes was realized by monitoring the increase of FITC fluorescence signal due to hydrophobic environment. The linear range of the detection of pure culture was from 1.4 × 10¹ to 1.4 × 10⁷ CFU/mL, with the detection limits as low as 0.88 CFU/mL and the coefficient of variation of each concentration no more than 2%. A good specificity of the detection system was also showed in the results, and the detection took about 70 min. Furthermore, the spiked samples of pork and milk were also tested by the detection system, and the recoveries ranged from 88.0% to 103.8%, with the coefficient of variation less than 12.8%. Taking advantages of sensitivity, rapidly and good selectivity, the proposed strategy in this study has great application potential in detection of foodborne pathogens in food.