Electrochemical immunoassay for the carcinoembryonic antigen based on Au NPs modified zeolitic imidazolate framework...

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. Graphical abstract Scheme 1 Schematic representation of fabrication of the immunosensor for CEA determination.