▎ 摘　　要

In this work, a novel electrochemical immunosensor was designed for ultrasensitive determination of carcinoembryonic antigen based on 3D-structured rGO/Ag-Au NPs. 3D-rGO-MWCNTs nanocomposites feature network structure which has a large specific surface area and excellent conductivity providing more active sites for Ag-Au bimetallic nanoparticles. At the same time, the synergistic effect of 3D-rGO-MWCNTs and Ag-Au NPs, significantly improved the electrochemical performance of the modified electrode. Due to the excellent biocompatibility of Ag-Au NPs, the antibody could be well attached to the electrode, and the immunosensor could be successfully prepared. Under the optimized conditions, the constructed immunosensor showed a wide linear range from 0.001 ng mL(-1) to 80 ng mL(-1) with the detection limit of 3 pg mL(-1) (S/N ratio of 3). The proposed immunosensor has excellent analytical performance including good stability, reproducibility and selectivity, and was successfully applied to the detection of CEA in human serum verified its practicability.