A fluorometric method for aptamer-based simultaneous determination of two kinds of the fusarium mycotoxins zearalenone and fumonisin B1 making use of gold nanorods and upconversion nanoparticles.

Abstract

An aptamer-based assay for the determination of two different kinds of fusarium mycotoxins, i.e., zearalenone (ZEN) and fumonisin B1 (FB1), is presented. Based on theinner filter effect (IFE) strategy, the contents of ZEN and FB1 can be simultaneously quantified. It is making use of 65-nm gold nanorods (AuNRs), 20-nm upconversion nanoparticles (UCNPs), fluorescence dyes, and DNA sequences. In the absence of ZEN and FB1, theUCNPs and AuNRs associate through DNA sequences. Due to IFE effect, weak fluorescence signals are collected. In the presence of ZEN or FB1, UCNPs and AuNRs become unstable and partially separate from each other. This results in the recovery of fluorescence signals. Under 980-nm laser excitation, the logarithmic values of fluorescence signal intensities at 606nm and 753nm gradually increase with the concentration of ZEN and FB1 in the ranges 0.05-100μgL-1 (the coefficient of determination is 0.997) and 0.01-100ngL-1 (the coefficient of determination is 0.986), respectively. The limits of detection (LOD) of the fabricated assay for ZEN and FB1 are0.01μgL-1 and 0.003ngL-1, respectively. The proposed methodhas a high selectivity over other competitive mycotoxins, including aflatoxin B1, ochratoxin A, patulin andochratoxin B. The applicabilityof the assay was evaluated in the determination ofZEN and FB1 contents in spiked corn samples. The average recoveries ranged from 89.9 to 106.6%. This result confirms the practicality of this method. Graphical abstract Schematic representation of an aptamer-based fluorometric method for simultaneous determination of two kinds of the fusarium mycotoxins zearalenone and fumonisin B1.