Growth of monolayer and multilayer graphene on glassy carbon electrode for simultaneous determination of guanine, adenine, thymine, and cytosine

Abstract

• Graphene (Gr) was grown vertically on a glassy carbon (GC) electrode with Au catalyst. • Monolayer and multilayer Gr films were deposited on GC to form a novel carbon electrode. • The carbon electrode responds directly to all four DNA bases and various other biomarkers. • The carbon electrode has excellent stability and reliability in DNA base analysis. A novel carbon film composed of glassy carbon (GC), monolayer graphene (Gr), and multilayer Gr was prepared by continuously growing Gr sheets on a GC substrate, using Au nanoparticles as catalysts. The formation of the monolayer Gr sheets and the vertical growth mechanism of the multilayer Gr sheets were investigated by analyzing the morphology, microstructure, and composition variations. The carbon multilayer film can recognize biomolecules and inorganic ions, and can respond to up to 10 species. This function is based on the inherent electrocatalytic activity of the carbon film without modification using additional sensitive materials. The use of the multilayer carbon film as an electrochemical biosensor was investigated with the four DNA bases: guanine (G), adenine (A), thymine (T), and cytosine (C). The carbon film clearly identified G, A, T, and C in a neutral electrolyte environment, with detection limits of 0.3, 0.4, 6.5, and 4.5 μM, respectively; the peak potential differences for A–G, T–A, and C–T were 164, 216, and 184 mV, respectively. This carbon film can replace commercial GC, Au, and carbon paste electrodes and function as a basic electrode to explore new electrochemical sensors with high functionality and sensitivity.