A DNA tetrahedral scaffolds-based electrochemical biosensor for simultaneous detection of AFB1 and OTA

[Display omitted] •DNA tetrahedral scaffolds improved detection accuracy and stability of electrochemical sensors.•Bifunctional work electrode greatly simplified the manufacturing process of biosensors.•HPG with the function of signal amplification was introduced for further improving sensitivity.•LOD of 2.4 and 3.5 pg/mL for OTA and AFB1 are qualified for the reliable monitoring of mycotoxins.•Dual-modality strategy provides a simple and accurate means for monitoring mycotoxins. Herein, a bifunctional electrochemical biosensor based on the DNA tetrahedral scaffolds (TDNs) was proposed, OTA@TDNs and AFB1@TDNs were adopted for electrochemical signal output in response to OTA and AFB1 concentration, simultaneously. In order to increase the conductivity of the biosensor, highly porous gold (HPG) was loaded on electrode surface by pulse electrodeposition. Under optimal conditions, the PFc displayed a linear range with AFB1 concentration between 0.05 ∼ 360 ng·mL−1 with the LOD of 3.5 pg·mL−1. And the PMB selective and sensitive responses to OTA are achieved with a linear range of 0.05 ∼ 420 ng·mL−1 and a LOD of 2.4 pg·mL−1. This biosensor has high sensitivity, selectivity and stability for OTA and AFB1 detection in peanut samples. The approach streamlines the experimental procedure, leading to significantly improve the detection efficiency of mycotoxins. Collectively, this method suggest a novel approach for the detection and monitoring of OTA and AFB1 in food sample.