A Novel Electrochemical Immunosensor for Prostate-Specific Antigen Based on Noncovalent Nanocomposite of Ferrocene Monocarboxylic Acid with Graphene Oxide

Abstract

A novel electrochemical immunosensor was developed for the determination of prostate-specific antigen based on immobilization of appropriate antibodies on gold nanoparticles and a poly-(2,6-pyridinediamine) modified electrode. The nanocomposite of ferrocene monocarboxylic acid hybridized graphene oxide was prepared by a π-π stacking interaction and was used as the electrochemical probe. A sandwich-type complex immunoassay was applied with polyclonal prostate-specific antigen antibodies labeled with the nanocomposite of ferrocene monocarboxylic acid hybridized graphene oxide. In order to improve the sensitivity, a potentiostatic method was used to reduce graphene oxide. Cyclic voltammetry and differential pulse voltammetry were employed to characterize the assembly process and the performance of the immunosensor. Under optimal conditions, the peak current of the immunosensor increased with concentration, showing a linear relationship between the peak current and the logarithm of the prostate-specific antigen concentrations in a wide range of 2.0 pg mL−1 to 10.0 ng mL−1 with a low detection limit of 0.5 pg mL−1. The immunosensor was used for the determination of prostate-specific antigen in serum.