Amperometric Immunosensors Based on Protein A Coupled Polyaniline-Perfluorosulfonated Lonomer Composite Electrodes

摘要

A very sensitive immunosensor based on polyaniline! Nafion/protein A (PA/NF/PrA) composite elecirodes has been developed for the amperometric immunoanalysis with urease-labeled immlmoreagents. The use of urease conjugated goat anti-RIgG (GaRIgG-Ur) as the labeled antibody and urea as the substrate with an amperometric detection at —200 mV (vs AgJAgCI) resulted in a dynamic range of 50—2000 ng mL-’ and a low detection limit of 10 ng/mL (64 pM) for the immunoanalysis of rabbit immunoglobulin G (RIgG). Because of the special affinity between protein A and RIgG, the PA/NF/PrA electrode can be regenerated repetitively by changing the pH of the buffer solutions. Characteristics of the PA/NF/PrA/RIgG immunosensor and optimal conditions k~r the competitive immunoanalysis of RIgG with FIA were studied.