CONICET | Buscador de Institutos y Recursos Humanos

α-zearalanol (ZEN) is a non-steroidal estrogenic agonist generated by chemical reduction of the mycotoxin zearalenone, which is produced by Fusarium spp and it is commonly found in contaminated grain products. ZEN has been widely used as growth promoter in the livestock production. Previous studies have shown their potential risk factor for breast cancer, with strong and prolonged endocrine-disruptive effects in humans at very low concentrations.In this work, we report the development of an electrochemical immunosensor for the determination of the growth promoter in bovine serum samples. The sensing scheme is based on a nanocomposite consisting of gold nanoparticles electrodeposited on multi-walled carbon nanotubes that were modified with poly(vinylpyridine) through in-situ polymerization. The electrodeposition of the gold nanoparticles enlarges the surface available for immobilization of antibodies against ZEN. The nanocomposite film was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, and cyclic voltammetry.Prior to the analysis of each serum sample, the unspecific binding of the modified AuNPs/MWCNTs-PVP/SPCE working electrode was blocked by treatment with BSA in PBS and then washed with PBS. Serum sample diluted was added to the immunosensor for. In this step, the ZEN present in the sample binds immunologically to the anti-ZEN antibodies. Then, the immunosensor was washed with PBS. Finally, the electrode was placed in desorption buffer (glycine-HCl) where ZEN was desorbed on the modified electrode surface and it was oxidized at +1.12 V. The calibration curve was obtained from 0.05 to 50 ng mL-1, with a detection limit of 16 pg mL-1. The calibration graph was described by the calibration equation ΔIpa (nA) = 3.12 + 19.30 CZEN with a correlation coefficient for this plot of 0.996. The intra-assay precision was 4.53 %, and the inter-assay precision was 5.92 % at the ZEN concentration of 25 ng mL-1.