A novel immunosensor based on an alternate strategy of electrodeposition and self-assembly

A novel amperometric immunosensor for the determination of carcinoembryonic antigens (CEA) was developed. Firstly, ordered multilayer films of Prussian blue (PB) and multiwalled-carbon nanotube/polyethylenimine/Au (MWNT–PEI–Au) nanocomposite were fabricated onto the surface of a glassy carbon electrode via alternate electrodeposition and self-assembly. Then a layer of chitosan mixed with gold nanoparticles was cast onto the surface of the electrode. Subsequently, the electrode was coated with antibody (Ab1) and blocked with BSA. The morphology of the MWNT–PEI–Au nanocomposite was characterized by transmission electron microscopy (TEM). The fabrication process of the ordered multilayer structure and immunosensor were characterized by scanning electron microscopy (SEM) and electrochemical measurements, respectively. The proposed fabrication strategy effectively ensured the stability of the Prussian blue as electron mediator. Under optimal conditions, the fabricated immunosensor exhibited a good response to CEA, with a detection range from 0.5 to 160 ng/mL and a detection limit of 0.08 ng/mL at 3δ. The current fabricated immunosensor exhibited good sensitivity, selectivity, and long-term stability. Furthermore, current study demonstrated the promising application of the alternate strategy based on electrodeposition and self-assembly for the construction of biosensor.