A new highly sensitive amperometric immunosensor for the detection of prostate specific antigen (PSA) has been constructed by means of covalent bonding to immobilize prostate specific antibody (anti-PSA) on multilayer organic-inorganic redox-active composite film/gold nanoparticle (nano-Au) modified glassy carbon electrode surface. The morphologies of the composite films were studied by means of scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) analysis was used to characterize the chemical composition in the PTC-NH2 compound. The preparation procedure of the immunosensor was further investigated by cyclic voltammetry (CV). In addition, the performance and influencing factors of the resulting immunosensor were studied in detail. Under optimal conditions, the resulting immunosensor displayed a high sensitivity for the detection of PSA, and responsed to the PSA concentration in the range from 0.5 to 16 ng/mL (R＝0.985) with a detection limit of 0.02 ng/mL. Moreover, the immunosensor exhibited high sensitivity, long-term stability and good selectivity.

Key words: amperometric immunosensor, prostate specific antigen (PSA), gold nanoparticle, Prussian blue, organic-inorganic redox-active composite film