Electrochemical process modulating colorimetry for dual-mode reliable detection of patulin based on target-induced DNA walker-triggered RCA-CHA cascade amplification

Patulin (PAT) is a toxic fungal metabolite widely present in nature, posing a significant threat to human and animal health. Herein, a self-powered sensing platform is developed for electrochemical/colorimetric detection of PAT, which leverages a target-induced DNA Walker-triggered rolling circle amplification (RCA) and catalytic hairpin assembly (CHA) cascade reaction, along with the synergistic catalysis of nanoenzymes and biological enzymes. In the detection system, the presence of PAT leads to the specific binding of the aptamer to activate the DNA Walker, which subsequently triggers the RCA-CHA cascade reaction, and then adsorbs abundant methylene blue to enhance the output signal. Under optimized conditions, the linear detection range of this method is 10⁻¹³-10⁻⁵ mg/mL, with detection limits of 2.8 × 10⁻¹⁴ mg/mL (electrochemical) and 1.8 × 10⁻¹⁴ mg/mL (colorimetric). The method is applied to detect PAT in banana samples with recoveries of 80.0–106.0 %, which demonstrates its high accuracy and significant potential for practical application.