title: Direct voltammetric detection of DNA and pH sensing on epitaxial graphene: an insight into the role of oxygenated defects.
abstract: In this paper, we carried out detailed electrochemical studies of epitaxial graphene (EG) using inner-sphere and outer-sphere redox mediators. The EG sample was anodized systematically to investigate the effect of edge plane defects on the heterogeneous charge transfer kinetics and capacitive noise. We found that anodized EG, consisting of oxygen-related defects, is a superior biosensing platform for the detection of nucleic acids, uric acids (UA), dopamine (DA), and ascorbic acids (AA). Mixtures of nucleic acids (A, T, C, G) or biomolecules (AA, UA, DA) can be resolved as individual peaks using differential pulse voltammetry. In fact, an anodized EG voltammetric sensor can realize the simultaneous detection of all four DNA bases in double stranded DNA (dsDNA) without a prehydrolysis step, and it can also differentiate single stranded DNA from dsDNA. Our results show that graphene with high edge plane defects, as opposed to pristine graphene, is the choice platform in high resolution electrochemical sensing.
authors: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543.
authors: Cheng Xiang
authors: CX
authors: Lim
authors: Hui Ying
authors: HY
authors: Hoh
authors: Priscilla Kailian
authors: PK
authors: Ang
authors: Kian Ping
authors: KP
authors: Loh
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis; D002244:Carbon / Q000737:chemistry*; D004247:DNA / Q000032:analysis*; D004277:DNA, Single-Stranded / Q000032:analysis; D004298:Dopamine / Q000032:analysis; D055664:Electrochemical Techniques / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D010100:Oxygen / Q000737:chemistry*
chemical_list: D004277:DNA, Single-Stranded; D002244:Carbon; D004247:DNA; D001205:Ascorbic Acid; D010100:Oxygen; D004298:Dopamine