Development of a novel lateral flow immunoassay based on Fe3O4@MIL-100(Fe) for visual detection of Listeria monocytogenes

Herein, a novel core-shell material Fe 3 O 4 @MIL-100(Fe) was synthesized for developing a novel LFIA by a two-step solvothermal method with good magnetic properties and high specific surface area. It was used as both magnetic separation and label agents in LFIA for the detection of Listeria monocytogenes . The enrichment of target bacteria can be achieved quickly and easily by direct adsorption of Fe 3 O 4 @MIL-100(Fe) on the bacteria and by the action of an applied magnetic field. It was beneficial in separation and concentration of target bacteria from food samples. The Fe 3 O 4 @MIL-100(Fe)-bacterial was then detected by the anti- Listeria monocytogenes antibody on the T line under the capillary action of the LFIA strip, resulting in the formation of a visible orange band. Under the optimal conditions, there was a good linear relationship between the intensity of the T line and the quantity of Listeria monocytogenes in the range of 10 5 -10 8 CFU mL − 1 , with a visual detection limit of 3.3 × 10 6 CFU mL − 1 . The strip showed strong specificity for L. monocytogenes , and the detection could be finished in 45 min, without the needing of pre-treatment. Thus, the proposed Fe 3 O 4 @MIL-100(Fe)-based strip was simple prepared, label-free, low cost, rapid and convenience.