FRET-based aptamer biosensor for selective and sensitive detection of aflatoxin B1 in peanut and rice

•We present a simple FRET-based assay for Aflatoxin B1 detection.•In this assay, aptamer-conjugated CdTe quantum dots were interacted with Au nanoparticles which led to fluorescence quenching of quantum dots.•The aptasensor showed a linear range between 10 and 400 nM.•This method was successfully applied for the analysis of AFB1 in rice and peanut samples.

Aflatoxins are potential food pollutants produced by fungi. Among them, Aflatoxin B1 (AFB1) is the most toxic. Therefore, a great deal of concern is associated with AFB1 toxicity. In this work, utilizing a FRET-based method, we have developed a nanobiosensor for detection of AFB1 in agricultural foods. Aptamer-conjugated Quantum dots (QDs) are adsorbed to Au nanoparticles (AuNPs) due to interaction of aptamers with AuNPs leading to quenching effect on QDs fluorescence. Upon the addition of AFB1, the specific aptamers are attracted to AFB1, getting distance from AuNPs which result in fluorescence recovery. Under optimized conditions the detection limit of proposed nanobiosensor was 3.4 nM with linear range of 10-400 nM. Selectivity test demonstrates that the nanobiosensor could be a promising tool for specific evaluation of food stuff. This method was successfully applied for the analysis of AFB1 in rice and peanut samples.