Water-dispersible graphene/amphiphilic pyrene derivative nanocomposite: High AuNPs loading capacity for CEA electrochemical immunosensing

In this work, a water-dispersible graphene/amphiphilic pyrene derivative nanocomposite has been synthesized for electrochemical immunosensing carcinoembryonic antigen (CEA). Water-soluble 4-armed poly(ethylene glycol)-NH2 is immobilized on graphene through noncovalent functionalization with the assistance of pyrene as an anchor group. The noncovalent functionalization strategy can significantly improve the hydrophilicity of graphene and loading capacity of gold nanoparticles (AuNPs) on graphene, resulting in efficient immobilization of antibodies on the nanocomposite. The morphology and conductivity of the as-prepared nanocomposites were characterized by scanning electron microscopy, Fourier transform infrared and UV-vis spectroscopy, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). CEA monoclonal antibody (anti-CEA) is immobilized on AuNPs via gold-thiol chemistry to construct the electrochemical immunosensing platform, and the surface binding events between anti-CEA and CEA is achieved by monitoring the change of the electrochemical impedance response. Under optimum conditions, the modified electrode exhibits a linear impedance response to CEA in a wide range of 0.1-1000 ng mL(-1) (R-2 =0.9959) with low detection limit of 0.06 ng mL(-1) (S/N=3). (C) 2017 Elsevier B.V. All rights reserved.