Abstract: Anti-zearalenone monoclonal antibodies (mAbs) were directionally conjugated on the surface of hydrazide group-functionalized gold nanoparticles because of the nucleophilic addition reaction between the aldehyde groups of the antibody Fc region and the hydrazide groups on gold nanoparticles (AuNPs). Compared with the carbodiimide-mediated covalent coupling method, the proposed directional coupling strategy showed several advantages such as use of less amounts of labeled antibody and shorter reaction time. The hydrazided gold nanoparticles-based immunochromatographic assay (hAuNPs-ICA) showed higher sensitivity for ZEN detection. Additionally, when hAuNPs-ICA was used to analyze ZEN-spiked maize samples, the average recoveries ranged from 83.1% to 118.0% with intra- and inter-batch coefficients of variation ranging from 3.9% to 13.1%, indicating good accuracy and precision.

Key words: immunoprobe; hydrazide; directional coupling; colloidal gold nanoparticles; zearalenone