An aptamer-based dipstick assay for the rapid and simple detection of aflatoxin B1

摘要

A rapid and simple dipstick assay based on an aptamer has been developed for the determination of aflatoxin Bl (AFBl). The dipstick assay format was based on a competitive reaction of the biotin-modified aptamer specific to AFBl between target and cy5-modified DNA probes. Streptavidin and anti-cy5 antibody as capture reagents were immobilized at test and control lines on a membrane of the dipstick assay. After optimization, the limit of detection for the dipstick assay was 0.1 ng/ml AFBl in buffer. The method was confirmed to be specific to AFBl, and the entire process of the assay can be completed within 30 min. Aqueous methanol (20%) provided a good extraction efficiency, and the matrix influence from corn extracts was successfully reduced through 2-fold dilution. The results of AFBl analysis for corn samples spiked with known concentration of AFBl by the dipstick assay and ELISA showed good agreement. The cut-off value of the dipstick assay for corn samples was 0.3 ng/g AFBl. Therefore, the dipstick assay is first reported and considered as a rapid, simple, on-site and inexpensive screening tool for AFBl determination in grains as well as a corn.