Cyclic voltammetry and quartz microbalance electrogravimetry of IgG and Anti-IgG reactions on silver

Abstract

A quartz crystal resonator is used in conjunction with cyclic voltammetry to study the binding of human IgG (Immunoglobulin G) and anti-IgG at a silver electrode. Results for the individual species in phosphate buffers of pH 7 and 12.7 are presented and compared with mixtures of the two. Anti-IgG is adsorbed over the entire potential range studied (0.2 to -0.9 V) and appears to undergo structural rearrangements of reduction. The antibody is adsorbed more strongly at pH 7 than at 12.7 and forms an insoluble precipitate at the electrode upon oxidation of silver. The quartz microbalance is suitable for qualitative studies of adsorption of these large molecular structures at a metal/electrolyte interface but, at this time, lacks the quantitative capability because of visco-elastic effects and solvent entrapment in the adsorbate which affect the response of the microbalance. © 1987.