A glassy carbon electrode modified with graphene nanoplatelets, gold nanoparticles and chitosan, and coated with a molecularly imprinted polymer for highly sensitive determination of prostate specific antigen

Abstract

The authors describe an amperometric assay for the detection of prostate specific antigen (PSA) that combines the advantages of using a molecularly imprinted polymer (MIP) and of a nanocomposite composed of graphene nanoplatelets (graphene sheets; GS), gold nanoparticles (AuNPs) and chitosan (Chit). The GS-AuNP composite was synthesized by a single-step reduction of GS and HAuCl4 solution. The MIP was synthesized by electropolymerization of dopamine and characterized by scanning electron microscopy and differential pulse voltammetry (DPV). Sensitivity is strongly improved by the magnified current obtained by using the GS-AuNP hybrid. Chit was further employed as a film-forming material to prevent the leakage of nanomaterials. Under optimized conditions, the method displays good analytical performance for the detection of PSA by DPV and by using hexacyanoferrate as the electrochemical probe. The peak current (typically measured at 0.16 V vs. SCE) increases linearly in the 1 pg mL−1 to 100 ng mL−1 PSA concentration range, and the detection limit is 0.15 pg mL−1 at a signal to noise ratio of 3. The method was successfully applied to the determination of PSA in serum. The assay is highly selective, sensitive, reproducible and stable. In our perception, it represents an attractive alternative to the commercially available ELISA kits for PSA.