Electrochemical Sensing and Biosensing Platform Based on Chemically Reduced Graphene Oxide

Abstract

In this paper, the characterization and application of a chemically reduced graphene oxide modified glassy carbon (CR-GO/GC) electrode, a novel electrode system, for the preparation of electrochemical sensing and biosensing platform are proposed. Different kinds of important inorganic and organic electroactive compounds (i.e., probe molecule (potassium ferricyanide), free bases of DNA (guanine (G), adenine (A), thymine (T), and cytosine (C)), oxidase/dehydrogenase-related molecules (hydrogen peroxide (H2O2)/beta-nicotinamide adenine dinucleotide (NADH)), neurotransmitters (dopamine (DA)), and other biological molecules (ascorbic acid (AA), uric acid (UA), and acetaminophen (APAP)) were employed to study their electrochemical responses at the CR-GO/GC electrode, which shows more favorable electron transfer kinetics than graphite modified glassy carbon (graphite/GC) and glassy carbon (GC) electrodes. The greatly enhanced electrochemical reactivity of the four free bases of DNA at the CR-GO/GC electrode compared with that at graphite/GC and GC electrodes makes the CR-GO/GC electrode a better choice for the electrochemical biosensing of four DNA bases in both the single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA) at physiological pH without a prehydrolysis step. This allows us to detect a single-nucleotide polymorphism (SNP) site for short oligomers with a particular sequence at the CR-GO/GC electrode without any hybridization or labeling processes in this work, suggesting the potential applications of CR-GO in the label-free electrochemical detection of DNA hybridization or DNA damage for further research. Based on the greatly enhanced electrochemical reactivity of H2O2 and NADH at the CR-GO/GC electrode, CR-GO/GC electrode-based bioelectrodes (in connection with glucose oxidase (GOD) and alcohol dehydrogenase (ADH)) show a better analytical performance for the detection of glucose and ethanol compared with graphite/GC- or GC-based bioelectrodes. By comparing the electrochemical performance of CR-GO with that of the conventional graphite and GC, we reveal that CR-GO with the nature of a single sheet showing favorable electrochemical activity should be a kind of more robust and advanced carbon electrode material which may hold great promise for electrochemical sensors and biosensors design.

Molecular Functionalization of Graphite Surfaces: Basal Plane versus Step Edge Electrochemical Activity

“…18 m diameter on a polishing wheel. The pipet was silanized using dichlorodimethylsilane to ensure a hydrophobic outer wall, before filling with a solution of 1 M AQDS in 0.05 M HClO 4 and inserting an AgCl coated Ag wire into each channel to serve as quasi-reference counter electrodes (QRCEs). The order of magnitude lower concentration of AQDS, compared to the macroscopic measurements, ensured that the evolution of AQDS adsorption at the microscale could be followed in real time.…”

“…[1][2][3][4] Glassy carbon (GC), boron doped diamond and graphite have long received attention for electroanalytical and electrocatalytic measurements, [5][6][7][8][9][10][11] and, more recently, carbon nanotubes and graphene have generated considerable interest. [12][13][14][15][16][17] However, despite well-defined bulk properties and structure, carbon materials can possess rather complex surface chemistry that may substantially impact the resulting electrochemistry.…”

One-step, solvothermal synthesis of graphene-CdS and graphene-ZnS quantum dot nanocomposites and their interesting photovoltaic properties

“…The unique sp 2 hybrid carbon nanostructure of GNs opens up new applications in nanoelectronics [3], biosensors [4,5], supercapacitors [6], and transistors [7]. Owing to their remarkable high electron mobility (15,000 cm 2 /V·s) [8], extremely large surface area (~2600 m 2 /g) [9], and low fabrication cost, GNs are considered as an ideal support for developing next-generation photovoltaic devices [10].…”

Signal enhancement in amperometric peroxide detection by using graphene materials with low number of defects

“…But size has huge influence on the sensitivity of the modified electrodes. The geometric area gives only a rough estimation, therefore chronocoulometric measurements in the presence of 0.1 mM K 3 [Fe(CN) 6 ] were performed in order to estimate Fig. 1 Microscopic pictures of electrodes prepared with different graphene materials: a SG, b CVDG and c rGO.…”

“…It has also been reported that carbon nanomaterials comprise electrocatalytic effects in amperometric detection systems [5]. Therefore numerous studies deal with graphene as electrode material in (bio) sensing applications [6], but often these materials are not exactly defined in their chemical structure, shape, size, or number of layers [7]. Even within the same production technique a poorly defined material will be received, often with slightly different properties from batch to batch.…”