Fumonisin B1 (FB1), a mycotoxin commonly produced by Fusarium verticillioides and classified as a group 2B hazard, has been identified in various food products; hence, sensitive and rapid analytical detection methods are needed. Since the first reported aptamer (96 nt ssDNA) for the highly specific molecular recognition of FB1, only 30 aptamer-based biosensors have been published. A critical point, yet commonly overlooked during the design of aptasensors, is the selection of the binding buffer. In this work, a colorimetric assay was designed by incubating a folded aptamer with FB1 and the subsequent addition of gold nanoparticles (AuNPs). The changes in the aggregation profile of AuNPs by a 40 nt aptamer and a 96 nt aptamer were tested after the addition of FB1 under different buffer conditions, where the incubation with Tris-HCl and MgCl2 exhibited the most favorable performances. The assay with the longest aptamer was specific to FB1 and comparable to other aptasensors with a limit of detection (LOD) of 3 ng/mL (A650/520 ratio). Additionally, the application of asymmetric-flow field-flow fractionation (AF4) with multidetection allowed for the analysis of the peak area (λ) and multi-angle light scattering (MALS) with LODs of up to the fg/mL level.

Mycotoxin contamination is a current issue affecting several crops and processed products worldwide. Among the diverse mycotoxin group, fumonisin B1 (FB1) has become a relevant compound because of its adverse effects in the food chain. Conventional analytical methods previously proposed to quantify FB1 comprise LC-MS, HPLC-FLD and ELISA, while novel approaches integrate different sensing platforms and fluorescently labelled agents in combination with antibodies. Nevertheless, such methods could be expensive, time-consuming and require experience. Aptamers (ssDNA) are promising alternatives to overcome some of the drawbacks of conventional analytical methods, their high affinity through specific aptamer-target binding has been exploited in various designs attaining favorable limits of detection (LOD). So far, two aptamers specific to FB1 have been reported, and their modified and shortened sequences have been explored for a successful target quantification. In this critical review spanning the last eight years, we have conducted a systematic comparison based on principal component analysis of the aptamer-based techniques for FB1, compared with chromatographic, immunological and other analytical methods. We have also conducted an <i>in-silico</i> prediction of the folded structure of both aptamers under their reported conditions. The potential of aptasensors for the future development of highly sensitive FB1 testing methods is emphasized.