Selection and identification of ssDNA aptamers recognizing zearalenone

AbstractZearalenone (ZEN) is a nonsteroidal estrogenic mycotoxin produced by Fusarium graminearum on maize and barley. Because most current methods of ZEN detection rely on the use of low-stability antibodies or expensive equipment, we sought to develop a rapid, low-cost determination method using aptamers instead of antibodies as the specific recognition ligands. This work describes the isolation and identification of single-stranded DNA (ssDNA) aptamers recognizing ZEN using the modified systematic evolution of ligands by exponential enrichment methodology based on magnetic beads. After 14 rounds of repeated selection, a highly enriched ssDNA library was sequenced and 12 representative sequences were assayed for their affinity and specificity. The best aptamer, 8Z31, with a dissociation constant (Kd) of 41 ± 5 nM, was successfully applied in the specific detection of ZEN in binding buffer and in real samples based on a magnetic separation/preconcentration procedure. This analytical method provided a linear range from 3.14 × 10−9 to 3.14 × 10−5 M for ZEN, and the detection limit was 7.85 × 10−10 M. The selected aptamers are expected to be used in the potential development of affinity columns, biosensors, or other analytical systems for the determination of ZEN in food and agricultural products. FigureDetermination of dissociation constant (Kd) and specificity of aptamers recognizing zearalenone