LAUSR

Abstract Allergic diseases have increased its incidence worldwide, increasing the significance of research in diagnostics to offer more precise immunotherapy options. Most current lines of work revolve around single-protein detection, which relies mostly on faint fluorescence signals and large expensive detectors. In this context, we propose a procedure based on visible light absorption by polymeric microparticles. The beads acting as supports react with the serum of an allergic patient and perform a magnetically-assisted competitive immunoassay, similar to indirect ELISA. Firstly, protein binding on surface and antibody recognition was evaluated by SEM imaging. Then, the procedure sensitivity was determined, were the lowest detected IgE concentration is comparable to commercial standards. Finally, the effects of cross-reactive allergen specimens were assessed, yielding difficulties in detection at antibody concentrations close to the limit of detection. Consequently, we have provided a proof-of-concept of a microparticle-based competitive immunoassay by visible light absorption analysis.