Fluorescent/electrochemical dual-signal response biosensing strategy mediated by DNAzyme-ferrocene-triggered click chemistry for simultaneous rapid screening and quantitative detection of Vibrio parahaemolyticus

To ensure the safety of food, rapid screening and quantitative detection of foodborne pathogens are both significantly required. In this work, a dual-signal response biosensing strategy integrated with the visual fluorescent signal and the quantitative electrochemical signal was developed to simultaneously satisfy these demands. The deoxyribozyme (DNAzyme)-ferrocene immobilized on the MXene/gold nanobipyramid/antimicrobial peptide was employed as the signal probe for dual signal output. In the presence of Vibrio parahaemolyticus (V.P, as the model analyte), the typical immunocomplexes between the signal probe, target, and capture antibody were formed on the sensing electrode. The DNAzyme with excellent catalytic ability allowed the click reaction of 3-azide-7-hydroxycoumarin and 3-butyn-1-ol with the assistance of copper ion (Cu2+) to provide the visual fluorescent signal for rapid screening. Then the ferrocene provided a quantified electrochemical detection signal to further confirm the foodborne pathogen contamination. Notably, the two signals provided a built-in cross-reference correction, which greatly improved the detection accuracy. Under optimum conditions, the proposed biosensing strategy exhibited a wide detectable range of 10–108 CFU·mL−1 and a low detection limit of 6 CFU·mL−1. This dual-signal biosensing strategy provides a useful route to develop simple and novel strategies for the on-site detection of foodborne pathogens.