A fluorescent aptasensor based on functional graphene oxide and FRET strategy simultaneously detects aflatoxins B1 and aflatoxins M1

Simultaneous and rapid detection of various mycotoxins in food holds significant practical importance in the field of food processing and safety. In this study, a fluorescent aptasensor based on functionalized graphene oxide (FGO) is developed for simultaneous detection of aflatoxin B₁ (AFB₁) and aflatoxin M₁ (AFM₁). The two aptamers specific to AFB₁ and AFM₁ are labeled with Cy3 and Cy5 respectively. Both the aptamers can be adsorbed onto the surface of FGO through π-π stacking, resulting in fluorescence resonance energy transfer (FRET) between the fluorophore and FGO. The absence of target leads to quenching of fluorescence while presence of either aflatoxin causes interaction between corresponding aptamer and target, leading to release from FGO surface thereby turning on fluorescence signal. The limit of detection (LOD) for AFB₁ is determined as 8.7 pg/mL whereas for AFM₁ it is found to be 20.1 pg/mL, demonstrating fast and sensitive detection capability using this approach. Furthermore, the aptasensor exhibits good specificity and selectivity even under influence from other common interfering toxins. With its simplicity in operation and portability features, this sensor has potential applications for establishing sensitive and portable on-site detection methods for various mycotoxins.