Optimizing Label-Free DNA Electrical Detection on Graphene Platform

Abstract

The anodized epitaxial graphene (EG) electrode demonstrates a high level of performance for electrochemical impedance as well as differential pulse voltammetry detection of immobilized DNA and free DNA, respectively, at solid-liquid interfaces. On the anodized EG surface, because of the presence of oxygen functionalities as well as π conjugated domains, the anchoring of the DNA probe can be achieved by either covalent grafting or noncovalent π-π stacking readily. The effect of different binding modes on the sensitivity of the impedimetric sensing was investigated. Equivalent circuit modeling shows that the sensitivity of EG to DNA hybridization is controlled by changes in the resistance of the molecular layer as well as the space charge layer. The linear dynamic detection range of EG for DNA oligonucleotides is in the range of 5.0 × 10(-14) to 1 × 10(-6) M. In addition, with the use of differential pulse voltammetry, single stranded DNA, fully complimentary DNA, as well as single nucleotide polymorphisms can be differentiated on anodized EG by monitoring the oxidation signals of individual nucleotide bases.

Enhancing the Surface Sensitivity and Selectivity: Functionalization of Carbon Nanomaterials

“…From the enzyme based sensor, the sensitivity of sensor with covalent attachment was improved compared to the one of non-covalently absorbed receptors. This was also in good agreement with the DNA recognition sensors [12]. In this case, an impedimetric sensor was built from anodized epitaxial graphene.…”

“…Independently of the approach, the functionalization procedure should be designed according to the sensors characteristics. The detection mechanism should be therefore taking into account so that the functionalization procedure enhances the sensitivity [12,20,43,48]. For such purpose, the functionalization requires suitable characterization tools that could give evidences of the effective immobilization of the receptor via quantitative and qualitative determination.…”

Insights into electrocatalytic activity of epitaxial graphene on SiC from cyclic voltammetry and ac impedance spectroscopy

“…Due to rather poor electrocatalytic activity of intrinsic graphene and graphite [25][26][27], the electrodes were activated by anodization [28,29]. It has been shown that during electrochemical oxidation, several functional groups connect to the graphite basal plane and many multivacancies and small etch pits appear [30].…”

Ultra‐Sensitive Graphene‐Plasmonic Hybrid Platform for Label‐Free Detection

“…A number of reports have appeared in the literature on the potential in sensitive and selective detection of protein and DNA using various graphene platforms. [22][23][24][25][26] Graphene has also been shown to be superior to metallic surfaces in terms of bio-compatibility and chemicalstability. [ 27 , 28 ] Molecular charge transfer between molecules and graphene has been shown to be signifi cant for selected families of molecules.…”