Detection of Aflatoxin B1 with a Label-Free Ellipsometry Immunosensor

The method of spectroscopic ellipsometry in total internal reflection mode (TIRE) was utilised for detection of Aflatoxin B1. The method of TIRE with the improved data analysis was capable of detection of aflatoxin molecules in low concentrations (down to 0.04 ng/ml) using a label-free and cost-effective direct immunoassay format. TIRE study of the binding kinetics yielded a large value of the association constant in the range of 106 l mol−1 which is typical for highly specific immune reactions. The comparison of the experimental data for three mycotoxins studied (e.g. aflatoxin B1, T-2 mycotoxin, and zearalenone) confirmed a common mechanism of the sensitivity boost due to the aggregation of hydrophobic molecules of mycotoxins in aqueous solutions.