A Sandwich-type Electrochemical Immunosensor using Ag@CeO2-Au as a Lable for Sensitive Detection of Carcinoembryonic Antigen

Abstract In this study, a sandwich-type electrochemical sensor was prepared to detect the carcinoembryonic antigen (CEA) sensitively by using silver@cerium oxide-gold (Ag@CeO2-Au) as carrier and gold nanoparticle - glassy carbon electrode (GCE) as platform. The Ag@CeO2 nanocomposite was prepared by selective REDOX method. Cerium (III) and silver (I) autocatalytic reactions do not require surfactants or organic compounds. In addition, CEA antibody (anti-CEA) was fixed by Au nanoparticles as a conductive matrix, and combined with Ag@CeO2-Au-anti-CEA to form a dual-signal amplification element mechanism. The immunosensor layer assembly process was validated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under the optimal conditions, the linear relationship between the current signal and CEA concentration in the range of 0.1 pg mL-1 to 5 ng mL-1. Linear equation was I (μA) = 5.77 logcCEA (ng mL−1) + 26.32, and the detection limit was 0.032 pg mL-1 (S/N = 3). The fabricated immunosensor has good specificity, high stability and reproducibility. Moreover, it has good detection performance in human serum and has a broad application prospect in CEA clinical and medical research.