Examination of an immunoglobulin modified methacrylate copolymer for amperometric immunoassay Original Research Article

A glycidyl and methyl methacrylate copolymer was successfully modified with immunoglobulin (IgG). This antibody binding caused a shift in the molecular weight profile and appeared to remove the lower molecular weight fractions of the copolymer, possibly by cross-linking. The IgG-modified copolymer coated on platinum electrodes could be used to monitor anti-IgG binding via the peroxide oxidation current produced by an enzyme label; this showed a high incidence of non-specific adsorption (∼50%) at concentration above ∼10 μg ml−1, but the specific reaction could still be successfully distinguished. By changing the polymer thickness, the reaction between IgG and anti-IgG could be deduced to occur at the outer sample interface of the polymer. The dose response curve for anti-mIgG–GOD at a mIgG-modified copolymer (m = mouse) indicated an analytically useful region below 2 μg ml−1 for the specific reaction. At these concentration levels non-specific adsorption is not seen.