A sensitive amperometric immunosensor for the detection of carcinoembryonic antigen using ZnMn2O4@reduced graphene oxide composites as signal amplifier

Abstract A novel amperometric immunosensor was designed and fabricated to sensitively detect carcinoembryonic antigen (CEA) using ZnMn2O4@reduced graphene oxide (ZnMn2O4@rGO) composites as signal amplifier. In this designed sensing platform, ZnMn2O4@rGO composites were facilely synthesized via a simple solvothermal process. The morphology and structure characteristics of composites were explored through scanning electron microscope, X-ray powder diffraction and X-ray photoelectron spectroscopy. The construction process of the immunosensor was monitored by cyclic voltammetry and A.C. impedance. The remarkable change in the electrocatalytic current of ZnMn2O4@rGO to H2O2 indicated the immunoreaction between antibody and CEA, resulting in sensitive detection of CEA with a broad linear range from 0.01 to 50 ng/mL (R2 = 0.9988) and a low detection limit of 1.93 pg/mL. Moreover, real human serum sample analysis demonstrated the availability of the immunosensor to monitor CEA as well as other tumor markers in clinical diagnosis.