Abstract
Fumonisin B1 (FB1), a mycotoxin classified as group 2B hazard, is of high importance due to its abundance and occurrence in varied crops. Conventional methods for detection are sensitive and selective; however, they also convey disadvantages such as long assay times, expensive equipment and instrumentation, complex procedures, sample pretreatment and unfeasibility for on-site analysis. Therefore, there is a need for quick, simple and affordable quantification methods. On that note, aptamers (ssDNA) are a good alternative for designing specific and sensitive biosensing techniques. In this work, the assessment of the performance of two aptamers (40 and 96 nt) on the colorimetric quantification of FB1 was determined by conducting an aptamer–target incubation step, followed by the addition of gold nanoparticles (AuNPs) and NaCl. Although MgCl2 and Tris-HCl were, respectively, essential for aptamer 96 and 40 nt, the latter was not specific for FB1. Alternatively, the formation of Aptamer (96 nt)–FB1–AuNP conjugates in MgCl2 exhibited stabilization to NaCl-induced aggregation at increasing FB1 concentrations. The application of asymmetric flow field-flow fractionation (AF4) allowed their size separation and characterization by a multidetection system (UV-VIS, MALS and DLS online), with a reduction in the limit of detection from 0.002 µg/mL to 56 fg/mL.
Highlights
Exposure to Fumonisin B1 (FB1) occurs in African [1] and Latin-American [2] countries and in several regions of Asia [3] and Europe [4]
This work presents a comparison on the performances of two aptamers for the colorimetric quantification of FB1
The results indicated that, along with the aptamer sequence, the selected buffer and incubation conditions play an important role in the final sensitivity and specificity of each assay
Summary
Exposure to FB1 occurs in African [1] and Latin-American [2] countries and in several regions of Asia [3] and Europe [4]. Fumosinins are a group of toxins generated by diverse fungi including Fusarium verticillioides [5], Alternaria alternata [6], Aspergillus niger [7], Tolypocladium cylindrosporum, Tolypocladium geodes and Tolypocladium inflatum [8]. Their chemical structure commonly consists of alkylamines, whose substitution of up to seven side chains allows the formation of different analogs, group B being the most common in nature [9]. Current conventional methods for mycotoxin detection, including enzyme-linked immunosorbent assay (ELISA), high-performance liquid chromatography with fluorescence detection (HPLC-FLD) and liquid chromatography-mass spectrometry (LC-MS), are costly, time consuming, are difficult to be applied on site and
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