Design and characterization of immunogens for raising antibodies directed towards chelated alkali metals

Abstract

The properties of immunogens synthesized from a calix[4]crown-6 were investigated with the aim of generating specific antibodies towards caesium chelates. Affinity capillary electrophoresis was successfully used to determine the stability parameters with caesium of both the hapten and the corresponding immunogens after coupling to bovine serum albumin (BSA). Unfortunately, the stability of the caesium chelate was shown to decrease drastically as the polarity of the medium increased. Nevertheless, the selectivity was proved to be rather stable, with a clear preference of caesium over potassium. The binding mechanism for the protein conjugates proved to be complex, as revealed by isotherms, whatever the number of calixarene groups coupled to BSA. Immunization of mice with caesium loaded immunogen resulted in the production of polyclonal antibodies able to distinguish between free calixarene and its complexes with either potassium or caesium.