Paper GR-ThP2
Ionic Strength Effects on Graphene Oxide Nanosheets and Flurescence Quenching of ssDNA Aptamers

Thursday, November 1, 2012, 6:00 pm, Room Central Hall

Recently, graphene has attracted considerable attention because of its remarkable electronics, its mechanical and optical properties, and its unique single-atom thickness and two-dimensional sp2 carbon networking material [1]. Graphene oxide (GO) presents excellent properties in high water dispersibility, capabilities of bridging biomolecules on the surface, and acts as a highly efficient fluorescent quencher material [2]. Sngle-stranded DNA (ssDNA) has been reported to bind on a graphene surface through non-covalent π-π interactions, whereas double-stranded DNA (dsDNA) cannot bind on graphene surfaces. Aptamers are synthetic, single-stranded DNA or RNA molecules that fold into unique 3D structures, and bind specifically to a wide range of molecules such as chemicals, proteins, and drugs. Therefore, aptamer-based GO biosensors have been developed for detecting various targets [3-5]. Ionic strength and pH are closely related to biochemical reactions and interactions between aptamer and targets. However, less studies have been reported to the ionic strength and pH effects on GO and interaction between GO and DNA [6]. Phosphate buffer saline (PBS) was commonly used as isotonic reagent for protein solution. In this study, the fluorescence intensity of GO significantly decreasing with increasing concentration of PBS. In addition, increasing quenching effect was found in the group with PBS as solvent for GO-aptamer interaction. The reported report are of importance in further applications of GO in biosensors and biochemical reactions.