Simple Electrochemical Immunosensor for the Determination of Rabbit IgG Using Osmuim Redox Polymer Films

Abstract

An amperometric immunosensor for the determination of rabbit IgG is proposed. The immunoassay utilizesa screen-printed carbon electrode on which osmium redox polymer is electrodeposited. This immunoassay detects0.1 ng/ml of rabbit IgG, which is ~ 102 fold higher than the most sensitive enzyme amplified amperometric immu-noassay. The assay utilizes a scren-printed carbon electrode which was pre-coated by a co-electrodeposited film ofan electron conducting redox hydrogel and a rabbit IgG. The rabbit IgG in the electron conducting film conjugatescaptures, when present, the anti-rabbit IgG. The captured anti-rabbit-IgG is labeled with horseradish peroxidase (HRP)which catalyzes the two-electron reduction of H2O2 to water. Because the redox hydrogel electrically connects HRPich converts the film from non-electrocatalytic to electro-catalytic for the reduction of H2O2 to H2O when the electrode is poised at 200 mV vs. Ag/AgCl.