Detection of food allergens using near-infrared fluorescent probes

Abstract

We aimed to detect the allergen proteins in food materials using recently developed near-infrared fluorescent probes. Sensitivities of this method were comparable to chemiluminescence detection methods, which are known to be sensitive. In addition, the sensitivities of this near-infrared fluorescent method were at least 10-50-times higher than those of the conventional visible fluorescent methods using Cy3 and Cy5 dyes. This method was effectively applicable to immunoblotting, dot-blotting and plate-assay (direct ELISA : fluorescence-linked immunosorbent assay) with ELISA plate. Allergen levels of the food sample were quantified by standard curves using standard allergen protein using the dot-blotting technique. This highly sensitive detection system also provided multiple detections of different allergens for different antibodies and dyes with distinct properties of wavelength. This enables high-throughput screening of characteristic allergen contents of target food materials, or cultivars. Generally, allergen proteins are recognized by patient's serum IgE. Therefore, we tried to detect patient's IgE-binding proteins, the putative allergens in foodstuffs. In this detection system, it was possible to detect IgE-binding proteins with sensitivity almost equivalent to a chemiluminescent detection system. Taken together, it was shown that this novel detection system was an effective technique for the sensitive detection and screening of food allergens.