Graphene‐Oxide‐Loaded Fe3O4‐Pd‐Ag Nanoparticles Allow Sensitive Detection of CEA through a Signal Enhancement Strategy**

Abstract

AbstractUsing graphene oxide (GO)‐loaded Fe3O4‐Pd‐Ag (GO/Fe3O4‐Pd‐Ag) nanoparticles on a gold electrode as a platform, an unlabeled electrochemical immunosensor was fabricated in this study to detect the carcinoembryonic antigen (CEA) with high sensitivity. After modification, the stability and strength of the signal are improved by the increased effective area of the electrode and the synergistic effect of the silver nanoparticles with GO, Fe3O4, and Pd. The signal intensity decreased as the concentration of CEA increased. Using cyclic voltammetry and electrochemical impedance spectroscopy, the immunosensor layer assembly process was validated. Under optimal conditions, the electrochemical immunosensor had a detection range of 1 pg mL−1 to 80 ng mL−1. The linear equation was I (μA)=304.563–41.867×logcCEA (ng mL−1), the correlation coefficient was 0.9967, and the detection limit was 0.2 pg mL−1. In addition, the modified electrochemical immunosensor exhibited high selectivity, stability, and repeatability. This electrochemical immunosensor shows a good application prospect in the detection of tumor marker CEA.