An electrochemical aptasensor based on dual-enzymes-driven target recycling strategy for patulin detection in apple juice

The presence of patulin (PAT) in fruits poses a threat to human health. Herein, a dual-enzymes-driven target recycling (dual-EATR) strategy-based PAT electrochemical aptasensor was constructed. The branched structure of the labeling material silver-palladium nanoparticles (AgPdNPs) can effectively load thionine (Thi). Gold nanoparticles (AuNPs)/Fe metal-organic frameworks (FeMOF)-PEI-GO with effective catalytic activity can amplify the redox signal of Thi. The presence of PAT could trigger the dual target recycling assisted by Exonuclease Ⅲ and Mg2+-dependent DNAzyme. The dual-EATR strategy gradually accumulates detection signals and can realize ultra-sensitive detection of PAT. With the optimal conditions, the developed aptasensor showed satisfactory performance with the range from 5 × 10−7 ng mL−1 to 5 ng mL−1 and a low detection limit of 0.217 fg mL−1. Compared with the chromatographic method, the developed aptasensor has consistent detection results. In addition, the aptasensor exhibited favourable selectivity, reproducibility and long-term stability. In the analysis of real samples, the aptasensor had good accuracy (recovery%, 91.0–103) and high precision (RSD%, 2.69–4.98), and relative error of <13% compared with the spiked concentration. It is proved with 95% of confidence level that the spiked sample tested generated a signal response not significantly different from the true value (p > 0.6). The feasibility of the aptasensor in apple juice samples has been verified, providing an excellent choice for the detection of trace PAT.