Selection and identification of ssDNA aptamers recognizing zearalenone

Zearalenone (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, 8Z(31), with a dissociation constant (K (d)) 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 x 10(-9) to 3.14 x 10(-5) M for ZEN, and the detection limit was 7.85 x 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.