A simple aptamer molecular beacon assay for rapid detection of aflatoxin B1

Aflatoxin B1 (AFB1) is a highly toxic mycotoxin, and rapid and sensitive detection of AFB1 is in demand for food safety and environmental analysis. Here we described a simple aptamer molecular beacon assay for rapid detection of aflatoxin B1 (AFB1) by using an aptamer with a fluorescein (FAM) label at the 5' end and a fluorescence quencher (black hole quencher 1, BHQ1) at the 30 end. In the presence of AFB1, the aptamer probe bound with AFB1 and induced a hairpin structure, drawing FAM and BHQ1 into close proximity and leading to fluorescence quenching. This assay allowed for a detection limit of 3.9 nmol/L and a dynamic range from 3.9 nmol/L to 4 μmol/L. Specificity test showed other mycotoxins including ochratoxin A, ochratoxin B, fumonisin B1, fumonisin B2, and zearalenone had negligible influence on detection of AFB1. AFB1 spiked in diluted liquor wine, methanol, or corn flour samples was successfully detected by using this aptamer probe, and the assay showed potential for real sample analysis.