Studies On The Development Of Biosensor Detection Of Aflatoxin B₁ And M₁ In Food Base On Aptamer Abstract

An aptamer-based fluorescent sensor for the rapid, sensitive and specific detection of Aflatoxin B1(AFB1) was developed in this study. Initially, a DNA/DNA duplex was formed between a fluorescein-labeled AFB1 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 AFB1, an aptamer/AFB1 complex was generated to release the quencher-modified DNA strand, thus recovered the quenched fluorescence of fluorescein and enabled quantitative detection for AFB1 by monitoring fluorescence enhancement. Under optimized conditions, this aptasensor exhibited a linear response to AFB1 concentration in the range of 5-100 ng·mL-1 with a detection limit down to 1.6 ng·mL-1. In addition, the proposed method maintained excellent specificity for AFB1 over other mycotoxins. Trials of this aptasensor in two brands of infant formula rice flour samples with satisfactory recovery in the range of 96.3%-106.8% and 93.0%-101.2%, respectively, demonstrate that the new aptasensor could be a potential sensing platform for AFB1 determination in food.A simple and fast aptasensor for the detection of aflatoxin M1 was developed based on structure-switching signaling aptamer. To construct the aptasensor, a fluorescein-labeled AFM1 aptamer hybridizes to a complementary DNA strand containing a quencher moiety, cause the quencher close to fluorophore and bring the fluorescence quenching. The introduction of AFM1 triggers forming an aptamer/AFM1 complex release the quencher containing DNA strand, thus generating a concentration-dependent fluorescent signal. The present aptasensor could provide both a low detection limit(1.7 ng·mL-1) and a wide linear detection range(5-100 ng·mL-1). Additionally, the proposed assay system exhibited high selectivity for AFM1 against other seven mycotoxins. The proposed sensing system was also applied to two brand non-contaminated infant formula rice flour samples spiked with a dilution series of AFM1, obtaining recoveries from 96.4%-103.6% and 95%-102.8% respectively. This detection technique has a significant potential for high-throughput, quantitative determination of mycotoxin levels in a large range of foods.