A Fluorescent Biosensor for Detection of Zearalenone

ABSTRACT A fluorescent biosensor was developed on a KinExATM flow spectrofluorimeter for the near real-time detection of soluble zeaalenone. Briefly, solutions of zearalenone and a monoclonal antibody directed against a protein conjugate of zearalenone, were incubated for thirty minutes to permit equilibrium binding to occur. The reaction mixture was then passed over a packed column of small beads (98 μm) whose surfaces were coated with a covalent conjugate of zearalenone and bovine serum albumin (BSA). Following a short wash with buffer to remove excess unbound primary reagents, the packed beads were subjected to a brief contact with fluorescein isothiocyanate-labeled polyclonal secondary antibody directed against the primary monoclonal, once again followed by a short wash. As this assay depends on the ability of soluble antigen to compete with immobilized antigen, increasing concentrations of zearalenone result in decreasing fluorescence observed on the bead pack. This assay is rapid (≅ 60 minutes) and can be adapted to various other analytes of interest.