title: Fluorescent aptamer-functionalized graphene oxide biosensor for label-free detection of mercury(II).
abstract: Label-free fluorescent detection of Hg(2+) has been realized via quenching of fluorescence of graphene oxide (GO). The water-soluble GO sheets, which are functionalized with single-stranded DNA aptamer, exhibit strong fluorescence emission at 600 nm under the excitation of 488 nm in the absence of Hg(2+) ions. When Hg(2+) ions appear in the aqueous solution, Hg(2+) ions are sandwiched between the hairpin-shaped double-stranded DNA due to the formation of the thymine-Hg(2+)-thymine complex, which holds the Hg(2+) ions in proximity to the surface of GO sheets. As a result, the fluorescence emission of GO is quenched. The present GO-based sensor shows a limit of detection as low as 0.92 nM and excellent selectivity toward Hg(2+) over a wide range of metal ions. The present work indicates that GO is a promising fluorescent probe for detection of metal ions and biomolecules.
authors.affiliation: Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV 26506-6106, USA.
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Xuejiao
authors.initials: X
authors.lastname: Zhou
authors.forename: Weiqiang
authors.initials: W
authors.lastname: Ding
authors.forename: Shouwu
authors.initials: S
authors.lastname: Guo
authors.forename: Nianqiang
authors.initials: N
authors.lastname: Wu
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006108:Graphite / Q000737:chemistry*; D008628:Mercury / Q000032:analysis*; D010087:Oxides / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000295:instrumentation*
chemical_list: D052157:Aptamers, Nucleotide; D010087:Oxides; D006108:Graphite; D008628:Mercury