Electrochemical immunosensor for prostate-specific antigen using a glassy carbon electrode modified with a nanocomposite containing gold nanoparticles supported with starch-functionalized multi-walled carbon nanotubes

We reported on a novel electrochemical immunosensor for the determination of prostate specific antigen (Pasa). It is based on gold nanoparticles supported on cross-linked starch functionalized multi-walled carbon nanotubes in a nanocomposite film. The method is simple and can be carried out at room temperature without the use of expensive chemicals or corrosive acids. Thus, it preserves the integrity and the electronic structure of the nanotubes. The stepwise assembly of the electrode was characterized by cyclic voltammetry (CV) and impedance spectroscopy. CV studies demonstrated that the formation of antibody-antigen complex decreases the peak current of the hexacyanoferrate redox pair linearly with increasing PSA concentration in two ranges (0.01-0.5 and 0.5-3.0 ng.mL-1). The detection limit for PSA is 7 pg.mL-1 (at S/N = 3). This immunoassay exhibits good sensitivity and reproducibility and may become a promising technique for the diagnosis and monitoring of prostate cancer. (author)