A novel aggregation-induced emission probe-linked phage sorbent assay for virulent bacteria strain imaging and on-site detection

It was critically important to develop some sensitive, rapid, and specific imaging or detection methods for the virulent strain in food safety monitoring. In the study, a novel tetraphenyl mono-phenylboronic acid dye (TPE-PBA) with good aggregation-induced emission (AIE) features and high combining capacity towards bacteria was first synthesized. With TPE-PBA as a signal tag, a sandwich-type AIE probe-linked phage sorbent assay was developed for imaging and detecting virulent strains using Escherichia coli O157:H7 (E. coli O157:H7) as a representative. In the assay, phages for E. coli O157:H7 were firstly fixed on the bottom of a 96-well plate to specifically capture the strain, then the TPE-PBA signal tag was added and incubated with the captured strain to produce the phage/E. coli O157:H7/TPE-PBA complex. The complex could produce intensive AIE fluorescence being proportional to the amount of E. coli O157:H7 with a detection limit of 30 CFU mL−1 within 30 min. Simultaneously, the strain could be imaged in the plate with good anti-photobleaching and AIE effects. The results demonstrated the AIE-linked phage sorbent assay with a TPE-PBA signal tag could provide a suitable platform for rapid and specific detection and imaging of virulent strains. Therefore, it exhibited good application prospects in the on-site monitoring of food pathogens.