Abstract:A fluorescent aptasensor was constructed based on photoinduced electron transfer using an amino-functionalized metal-organic framework (MOF) from the University of Oslo 66 (UiO-66-NH2) and fluorescently labeled aptamers for the determination of aflatoxin B1 (AFB1). Tetramethylrhodamine-labeled (TAMRA-labeled) aptamers (TAMRA-aptamer) were absorbed onto the surface of the UiO-66-NH2 via π-π stacking and the fluorescence of the TAMRA-aptamer was quenched due to the photoinduced electron transfer. The conformation of TAMRA-aptamers, which specifically recognize and bind to AFB1, changed from a single chain to a stable internal loop, and the hindrance of photoinduced electron transfer due to the weak binding ability between the internal loop structure and UiO-66-NH2 led again to fluorescence of the TAMRA-aptamers. The fluorescent aptasensor is thus considered suitable for AFB1 detection to as low as 0.50 ng/mL. The intensity was proportional to AFB1 concentration in the range between 1.00 and 100.00 ng/mL, and the square of the correlation coefficient (R2) was 0.994. The recovery for the detection of AFB1 in red wine was 90.00~101.00%. The developed method is simple, inexpensive, reasonably selective, and highly sensitive and can be used for the rapid determination of AFB1 in red wine.
