A rapid fluorometric method for determination of aflatoxin B 1 in plant-derived food by using a thioflavin T-based aptasensor

Abstract

A fluorometric aptamer-based method is described for the determination of aflatoxin B 1 (AFB 1 ). The fluorescent dye thioflavin T (ThT) forms a complex with the aptamer against AFB 1 (aptamer/ThT), and the fluorescence of the complex is strongly enhanced. On addition of AFB 1 , it will bind to the aptamer and release ThT. The fluorescence of free ThT is much weaker. The fluorescence of the system, best measured at excitation/emission wavelengths of 440/487 nm, drops gradually in the AFB 1 concentration range from 0.2 to 200 ng·mL −1 , exhibiting good linearity. The detection limits are 0.2 ng·mL −1 in buffer solution, and 1 ng·mL −1 when applied to plant-derived food. The recovery of AFB 1 from spiked foodstuff ranges from 74.7% to 121%. The assay can be performed within 20 min. [Figure not available: see fulltext.].