Functional nanozyme mediated multi-readout and label-free lateral flow immunoassay for rapid detection of Escherichia coli O157:H7.

Abstract To overcome the drawbacks of antibody labeling dependence and single-readout system in the conventional lateral flow immunoassays (LFIAs) as well as the non-targeted combination of new capture agents reported recently for pathogen detection, in this work, a multi-readout and label-free LFIA was proposed for rapid detection of Escherichia coli O157:H7 (E. coli O157:H7) based on a nanozyme-bacteria-antibody sandwich pattern. A type of functional nanozyme—mannose modified Prussian blue (man-PB), was introduced as the recognition agent as well as signal indicator. Apart from original signal intensity on the T-line, the peroxidase-like catalytic activity-driven generation of colorimetric signal could be used as another format of quantitation. Importantly, such LFIA could exhibit excellent performance for target pathogens detection separately with a quantitative range of 102–108 cfu·mL−1 and a low detection limit of 102 cfu·mL−1 based on different readout formats, indicating the application potential of the proposed LFIA in real samples.