A simple aptamer-based fluorescent assay for the detection of Aflatoxin B1 in infant rice cereal

A fluorescent assay for the rapid, sensitive and specific detection of Aflatoxin B-1 (AFB(1)) was developed in this study. Initially, a DNA/DNA duplex was formed between a fluorescein-labeled AFB(1) aptamer and its partially complementary DNA strand containing a quencher moiety, resulting in fluorescence quenching due to the close proximity of fluorophore and quencher. Upon the addition of AFB(1), an aptamer/AFB(1) complex was generated to release the quencher-modified DNA strand, thus recovered the fluorescence of fluorescein and enabled quantitative detection for AFB(1) by monitoring fluorescence enhancement. Under optimized conditions, this assay exhibited a linear response to AFB(1) in the range of 5-100 ng/mL with a detection limit down to 1.6 ng/mL. Trials of this assay in infant rice cereal with satisfactory recovery in the range of 93.0%-106.8%, demonstrate that the new assay could be a potential sensing platform for AFB(1) determination in food. (C) 2016 Elsevier Ltd. All rights reserved.