An automated amperometric immunosensors for the quantification of transferrin was fabricated using two monoclonal IgG class anti-rat transferrin antibodies, 15C2H3 and 22A06D2. The former was immobilized on a gold electrode, while the latter was conjugated with the positively charged polymers containing ferrocenyl groups. The quantitative analysis of transferrin was investigated by measuring the electrooxidation current of ferrocene, which is proportional to the transferrin concentration for the equivalently observed sandwich formation. The deposition of electroconductive polymers, polypyrrole (poly-P) and poly⌈ferrocenyl-methyl-3-(pyrrol-l-yl)propyldimethylammonium bromide⌉ (poly-FP), were performed on the surface of antibody-immobilized gold electrode in order to increase the efficiency of the electron transfer between the antibody-cojugated ferrocence and the gold electrode, and to eliminate the nonspecific binding of ferrocene-labeled antibody by a mutual repulsion.
