Development of an aptasensor for the fast detection of Versicolorin A

Aflatoxins (AFs) are secondary metabolites produced by Aspergillus flavus and Aspergillus parasiticus. The molds may contribute to pre-harvest aflatoxin contamination of susceptible crops. For the customer and food producer, a predictive model for aflatoxin detection is very desirable. Versicolorin A (VerA), which is the first precursor in the pathway of aflgoxin B-1 (AFB(1)) biosynthesis, shares similar toxic group with the furofuran structure in aflatoxin B-1. VerA exhibits a much lower teratogenic toxicity than AFB(1) and may be used as a predictive indicator for aflatoxin B-1 contamination of storage crops. Therefore, the development of a fast detection method for VerA is important. One of the randomly computer-generated aptamers of VerA was confirmed by isothermal titration calorimetry with K-d = 9.26 x 10(-6) mol l(-1). In addition, a simple and sensitive label-free aptasensor was developed for the electrochemical detection of VerA. According to the results from differential pulse voltammetry (DPV), a linear relationship existed between the log conc. of VerA (ranged from 0.01 to 100 ng ml(-1)) and the current (Delta I-p) with a limit of detection (LOD) of 10 pg ml(-1). The resulting aptasensor exhibited good reproducibility for detecting VerA and stability after storage for 15 days at 4 degrees C with acceptable anti-interference against ZEN, OTA, DON, and FB1. When used in corn samples, the recoveries of VerA were determined to be in the range of 81.3% -104.4 %. Although with some intercross, result suggests that the obtained aptamer for VerA is potentially used as a sorbent for the preparation of solid-phase-extraction procedure to clean up food samples in conjunction with high-performance liquid chromatography analysis. (C) 2015 Elsevier Ltd. All rights reserved.