An ATP-fluorescence dual-mode biosensing platform for rapid broad-spectrum enrichment and detection of bacteria based on PEI-functionalized magnetic UiO-66-NH2

Abstract

Bacteria-induced food pollution poses a serious threat to human health. To detect early and sensitive traces of bacteria in food, a poly (ethyleneimine) (PEI)-modified magnetic organic framework material (FeO@UiO-66-NH@PEI) was prepared for broad-spectrum enrichment and dual-mode detection of typical gram-positive bacteria (Bacillus subtilis, B. subtilis) and gram-negative bacteria (Escherichia coli, E. coli) using Schiff’s base reaction. Due to the positive charge caused by the abundance of amino groups, FeO@UiO-66-NH@PEI exhibited rapid enrichment of E. coli and B. subtilis within 12 min through the electrostatic interaction with bacteria. The biosensor based on FeO@UiO-66-NH@PEI achieved sensitive detection of E. coli and B. subtilis using the adenosine triphosphate (ATP) bioluminescence technology within the detection range of 10-10, and the detection limits were 44 and 57 CFU/mL, respectively under optimal experimental conditions. Moreover, a fluorescence platform was constructed by FeO@UiO-66-NH@PEI to achieve more diversified detection and reliable detection results for E. coli and B. subtilis. Within the detection range of 10-10, FeO@UiO-66-NH@PEI exhibited satisfactory linearity with detection limits of 6 CFU/mL and 14 CFU/mL. This biosensor using ATP bioluminescence and fluorescence technology showed remarkable recoveries (85.3–108.5 %) for E. coli and B. subtilis in biscuit matrices, indicating a bright prospect of the dual-mode platform for bacteria detection in food.