Two-Site Antibody Immunoanalytical Detection of Food Allergens by Surface Plasmon Resonance

Bovine protein β-lactoglobulin (βLG) and peanut protein Ara h1 are considered good targets for detecting milk and peanut allergen, respectively. We used surface plasmon resonance (SPR) to detect βLG and Ara h1 by immobilizing the affinity-purified monoclonal antibodies on the biosensor chip. Proteins that bound to the antibody surface were detected by a shift in resonance angle. Adding polyclonal antibodies in the sandwich assay enhanced the sensitivity. βLG and Ara h1 were detected at 5.54 and 0.77 ng/mL, respectively, by SPR, and the results demonstrated good linear relation with relatively low concentrations of protein. The limit of detection with SPR was comparable to that with sandwich enzyme-linked immunosorbent assay (S-ELISA) with the same polyclonal and monoclonal antibodies. Use of the SPR biosensor is a simple, fast, and reliable way to detect βLG and Ara h1.