Abstract

An electrochemical immunoassay for the carcinoembryonic antigen is described. It is based on the use of Au NPs modified zeolitic imidazolate framework (ZIF-8) and ordered mesoporous carbon (OMC). Au NPs@ZIF-8 was synthesized by reduction of chloroauric acid. It serves as immobilization support nanocarrier to increase antibody loading due to its large surface area. OMC was dropped on a glassy carbon electrode to improve electrochemical signals due to enhanced electrical conductivity. Differential pulse voltammetry was carried out to record electrochemical responses (best measured at 0.26 V vs. Ag/AgCl). The immunosensor demonstrated excellent electrochemical performance with a linear determination range of 5 pg mL −1 to 400 ng mL −1 and a determination limit of 1.3 pg mL −1 ( S / N  = 3). The sensor also exhibited high selectivity, good stability, and acceptable reproducibility. Scheme 1 Schematic representation of fabrication of the immunosensor for CEA determination