Amperometric enzyme immunoassay sensors in determination of Fusarium oxysporum antigens

Abstract

Enzyme immunoassay sensors (EIS) with L-cysteine desulfhydrase (CDH) as a label based on planar graphite electrodes were created to determine Fusarium oxysporum antigen (Ag). The EIS action relies on the combined effect of immunological, enzymatic, and electrochemical reactions. The immunosensors developed allow the determination of Fusarium oxysporum Ag in the concentration range of 5?10–10 – 5?10–6 mg/mL with the limit of quantification of 1?10–10 mg/mL. The binding constant of the Ab-Ag immune complexes was estimated as Ка1 = (6.2 ? 0.2)?109 (mg/mL)–1. No cross-reaction with Ag of such pathogenic fungi as Alternaria alternata, Cladosporium herbarum, Aspergillus fumigatus, and Aspergillus niger was confirmed. Here the quality of wheat groats was assessed to test the methods for the determination of Fusarium oxysporum Ag using the developed CDH immunosensor.

Keywords

• fusarium oxysporum
• enzyme immunoassay sensor
• l-cysteine desulfhydrase
• fungal pathogens