A sensitive label-free amperometric CEA immunosensor based on graphene-nafion nanocomposite film as an enhanced sensing platform.

A novel approach to fabricate a label-free amperometric immunosensor for the detection of carcinoembryonic antigen (CEA) was described. Herein, methylene blue (MB), gold nanoparticles (AuNPs) and carcinoembryonic antibody (anti-CEA) were layer-by-layer assembled on the graphene-Nafion nanocomposite film-modified electrode by means of a self-assembling technique and the opposite-charged adsorption. Subsequently, the stepwise self-assembling procedure of the immunosensor was further characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS).