An amperometric immunosensor based on an electrochemically pretreated carbon–paraffin electrode for complement III (C 3) assay

Abstract

An electrochemical immunosensor based on the adsorption of anti-complement III antibody onto an electrochemical pretreated carbon–paraffin electrode has been proposed for the detection of complement III (C 3). The competitive immunoassay format was adopted with horseradish peroxide–C 3 (HRP–C 3) as a tracer, 3,3′5,5′-tetramethylbenzidine (TMB) and hydrogen peroxide as the enzyme substrates. In order to measure the amount of HRP–C 3 binding onto the electrode surface, the product of the enzyme catalytic reaction was detected at 100 mV (vs. Ag/AgCl reference electrode). The system was optimized to realize a reliable determination of C 3 in the range of 0.06–10 μg/ml. It exhibits some advantages, such as simplicity of fabrication, rapidity of measurement, and satisfactory sensitivity and reproducibility.