A fluorescent aptasensor based on MoSe2 nanosheets and exonuclease III-assisted signal amplification for sensitive detection of ZEN

Abstract

Current detection methods for trace mycotoxins in the environment suffer from false negatives, false positives, or low accuracy. Therefore, it is important to establish a sensitive and efficient mycotoxin detection method for food safety. In this study, a novel fluorescent aptamer sensor is proposed by interacting layered MoSe₂ nanosheets (MoSe₂ NSs) with a zearalenone (ZEN) aptamer-functionalised FAM probe (Apt-FAM) that specifically binds to ZEN. The proximity of the fluorescent moiety FAM to MoSe₂ NSs resulted in fluorescence quenching. With the presence of ZEN, Apt-FAM can specifically bind ZEN. Using ribonucleic acid exonuclease III (Exo III) as an auxiliary signal amplification and triggering surface desorption of MoSe₂ NSs allows fluorescence signals to be recovered. Under optimal conditions, the sensor had a detection range of 0.05–100 ng/mL. The limit of detection (LOD) for ZEN in the range of 0.05–1 ng/mL was 6.4 pg/mL and the LOD for ZEN in the range of 5–100 ng/mL was 4.4 pg/mL. Furthermore, the aptasensor successfully measured ZEN levels in commercially bought corn and beer with satisfactory results.