Target-triggered dual cycling signal amplification: a strategy for sensitive and specific zearalenone biosensing

Zearalenone (ZEN) is a mycotoxin widely found in common food grains and by-products, seriously threatening human health. With the increasingly stringent requirements for the detection of ZEN, conventional electrochemical sensors have failed to meet practical demands, so the coupling of multiple amplification strategies has emerged as a mainstream method to boost the performance of electrochemical sensors. Herein, a target-triggered cascade signal amplification strategy for the electrochemical detection of ZEN was developed by combining enzyme-assisted dual cycling with the hybridization chain reaction (HCR). In the presence of the target, the initiation of the dual cycle led to the generation of trigger probes, which turned on HCR assembly to produce an abundance of long double-stranded DNA (dsDNA), resulting in a higher electrochemical signal. Under the optimal experimental conditions, the strategy exhibited good linearity in the detection range of 1.0 × 10^-12 mol L^-1 to 1.0 × 10^-7 mol L^-1 with a detection threshold of 5.0 × 10^-13 mol L^-1. Meanwhile, the aptasensor demonstrated high specificity toward ZEN, which was virtually unaffected by competing mycotoxins. It also exhibited commendable stability and reproducibility. The electrochemical assay pioneers a novel solution for expeditious and precise ZEN detection.