Surface Plasmon Resonance for Rapid Screening of Uranyl Affine Proteins

A sensitive immunoassay based on SPR analysis was developed to measure uranyl cation (UO2 2+) affinity for any protein in a free state under physiological conditions. The technique involves immobilization of a specific monoclonal antibody (mAb) raised against UO2 2+ and 1,10-phenanthroline-2,9-dicarboxylic acid (DCP) used as a probe of UO2 2+ captured by the mAb. Calibration curves were established for accurate determination of UO2 2+ concentrations with a detection limit of 7 nM. The remaining free UO2 2+ could be accurately quantified from the different protein-metal equilibrium and a dose−response curve established for K D determination. This generic method was applied not only to proteins such as transferrin and albumin but also to small phosphonated ligands. Its robustness allows the fast UO2 2+ K D determination of any kind of macromolecules and small ligands using very few amount of compounds, thus opening new prospects in the field of uranium toxicity.