A dual-modal biosensor coupling cooperative catalysis strategy for sensitive detection of AFB1 in agri-products.

[Display omitted] • Cooperative catalysis between HRP and nanocomposite improved sensitivity of sensor. • DNA-switching protocol toward AFB 1 overcomes complex matrices interference. • The limit of 0.2 pg/mL for AFB 1 is qualified for the safety inspection of AFB 1. • Dual-modality strategy provides an accurate means for monitoring trace pollutants. Herein, the cooperative catalysis effect between nanocomposite (AgPd NPs/POD-M/PEI-rGO) and horseradish peroxidase (HRP) was applied for the fast and sensitive detection of aflatoxin B1 (AFB 1). Upon specific and competitive binding of HRP@DNA and AFB 1 to cDNA, the working electrode presented different catalytic capacities for supporting electrolytes (TMB and H 2 O 2). In the redox mechanism of TMB and H 2 O 2 , HRP and nanocomposite effectively catalyzed the oxidization of TMB to form the one-electron oxidation intermediate TMB+, and contributed the electrical signals and absorbance signals. Electrochemistry and colorimetric analyses were successfully realized for AFB 1 detection with 0.2 pg/mL and 8 pg/mL of detection limits, respectively, which is much lower than that of traditional HPLC methods. Overall, this method had significant reliability and sensitivity, offering a promising potential for conveniently evaluating the quality of agri-products polluted with AFB 1. Moreover, this approach provides a new idea for fast and accurate detection of mycotoxin. [ABSTRACT FROM AUTHOR]