Label-free photonic crystal immuno-assay for zearalenone-type mycotoxins

Zearalenone (ZEN) and its metabolites are major mycotoxins commonly found in cereals and cereal-based products, posing significant risks to food safety and human health. Therefore, developing effective methods to detect ZEN and its primary metabolites is crucial. In this study, a label-free optical sensing platform based on the photonic crystal immuno-hydrogel (PCIH) was presented. We developed a competitive immunoassay for the broad-spectrum detection of zearalenone-type mycotoxins (ZEN, α-zearalenol (α-ZEL), and β-zearalenol (β-ZEL)), using the antibody 3D4, which specifically targets ZEN and its metabolites, as the recognition element, and photonic crystal hydrogel (PCH) as the carrier. The PCIH sensor demonstrated good linearity for ZEN, α-ZEL, and β-ZEL across a concentration range of 1-150 ng/mL, with limits of detection (LODs) of 1.97, 2.06, and 2.07 ng/mL, respectively, while exhibiting excellent selectivity against interfering substances. The sensor also exhibited good reusability after five regeneration cycles and maintained stable performance after 21 days of storage. Furthermore, the sensor was successfully applied to detect zearalenone-type mycotoxins in corn grits, wheat flour, and rice samples, showing strong reliability and practicality. This PCIH sensing platform is simple to operate and label-free, offering a promising and efficient approach for monitoring zearalenone-type mycotoxins in food.