▎ 摘　　要

A new electrochemical immunosensor for the determination of carcinoembryonic antigen (CEA) was developed with a Graphene (Gr)-Prussian blue (PB)/gold nanoparticles (GNP) immobilization platform. HRP-anti-CEA was immobilized on the platform and with the immunoreactions, the formed immunocomplex inhibited partly the bioactive center of the immobilized HRP, and decreased the HRP toward the reduction of H2O2, which was the base of the detection of CEA. The Gr-PB/GNP can be used not only as the electrochemical redox mediator but also to enhance the sensitivity. Under optimal experimental conditions, the proposed immunosensor for CEA was observed with an ultra low limit of detection equal to 3 pg mL(-1) (at 3 sigma), and the linear working range spanned from 0.01 to 1.0 and 1.0 to 60 ng mL(-1). Moreover, the immunosensor was examined for use in the determination of CEA in real human serum specimens. The assayed results of serum samples with the sensor received an acceptable agreement with the reference values. Importantly, the methodology provides a promising ultra sensitive assay strategy for clinical applications.