A novel electrochemical immunosensor for determination of carcinoembryonic antigen (CEA) in human serum was fabricated by depositing Mo–Mn3O4/MWCNTs/Chits nanocomposite onto an indium-tin oxide (ITO) electrode. Mo-doped Mn3O4 (MMO) was synthesized by sol–gel method and the presence of molybdenum improved its electrochemical properties. The MMO/MWCNTs/Chits nanocomposite could accelerate the electron transfer rate and enlarge the surface area to capture a large number of Carcinoembryonic Antigen (CEA). The factors influencing the performance of the immunosensor were investigated, such as incubation time, incubation temperature and pH. Under optimal conditions, the electrochemical immunosensor could detect CEA in a linear range from 0.1ng⋅mL−1 to 125ng⋅mL−1 with a detection limit of 4.9pg⋅mL−1 (S∕N=3). In addition, it exhibited high sensitivity and acceptable stability on a promising immobilization platform for signal amplification, which could be extended to other labeled recognition systems. This electrochemical immunosensor may provide potential applications for the clinical diagnosis.
