A fluorescence method for detection of aflatoxin B1 based on structural change of unlabeled aptamer

A simple method was constructed for fluorescence detection of aflatoxin B1 (AFB1) based on the structural change of an unlabeled aptamer. In the absence of AFB1, an unlabeled AFB1 aptamer simultaneously hybridized with two complementary short DNA strands, forming a DNA duplex structure. As results, the fluorescein FAM labeled at 3’ end of a complementary DNA was adjacent to the quencher BHQ1 labeled at 5’ end of the other complementary DNA. In this case, fluorescence resonance energy transfer occurred, and FAM fluorescence was quenched by BHQ1. In the presence of AFB1, the aptamer bound to AFB1 instead of hybridizing with complementary DNAs. As results, FAM and BHQ1 were far away from each other, and FAM fluorescence could not be quenched. AFB1 was quantitatively detected by measuring fluorescence intensity of the system. Detection limit of this method was 0.2 nmol/L, and quantitative detection range was 1.0 nmol/L-4.0 µmol/L. This method could be used for rapid detection of AFB1 in complex matrix samples for not requiring labeling of aptamer, easy to operate, and good specificity. © 2024, Youke Publishing Co.,Ltd. All rights reserved.