Construction of polydopamine-coated three-dimensional graphene-based conductive network platform for amperometric detection of dopamine

Abstract An effectively sensitive and selective electrochemical sensor based on polydopamine (PDA)-coated material was fabricated for the dopamine (DA) amperometric detection. The coated compounds were synthesized through incorporating carbon black (CB) nanoparticles into graphene oxide (GO) sheets via spray-drying technique to obtain three-dimensional (3D) CB-GO microsphere structure (CG). Electrochemical characterizations of the PDA-CG modified Pt electrode (PDA-CG/Pt) were carried out through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), revealing an excellent conductivity activity against other electrodes in this study, which comes down to the synergistic effect of the introduction of CB nanoparticles and the presence of PDA layer. The sensor prepared by this facile approach without containing any metal elements also shows superior catalytic performance towards oxidation of DA, regardless of the existence of other interference including glucose (Glu), uric acid (UA) and ascorbic acid (AA). The linear range for amperometric detection of DA was from 0.2 to 63 μM, and the detection limit was 0.048 μM (S/N=3). Furthermore, this modified biosensor could be successfully applied to determine DA in biological fluids of human serums with satisfying results.