▎ 摘　　要

In this study, a sensitive electrochemical immunosensor for prostate specific antigen (PSA) detection is described using nitrogen-doped graphene (NG) and gold nanoparticles (Au NPs) as a sensing interface. In this design, a PSA antibody (Ab) was first immobilized on the surface of NG decorated with Au NPs, and an aptamer labelled with ferrocene (Fc) was used as a signal probe. In the presence of PSA, a sandwich structure of Ab-PSA-aptamer was formed via specific recognition. Differential pulse voltammetry (DPV) was employed to record the electrochemical signal of Fc in phosphate-buffered saline (PBS) containing 0.10 M NaClO4. Under the optimal experimental conditions, the electrochemical immunosensor displayed a wide linear response range (0.05 ng mL(-1) to 100 ng mL(-1)) and low detection limit (0.017 ng mL(-1) (at S/N = 3)). Further, the immunosensor was evaluated with a serum sample, and satisfactory results were obtained.