title: [Study on MSO/GO-based determination method for trace amount of aqueous Hg2+].
abstract: OBJECTIVE
  To establish a highly sensitive fluorometric nanobiosensor for determination of aqueous mercury ions (Hg(2+)) using optimized mercury-specific oligonucleotide (MSO) probes and graphene oxide (GO).
  
  
  METHODS
  The nanobiosensor was assembled by attaching the self-designed MSO(1) (5' end labeled with fluorophore carboxyfluorescein (FAM), denoted as FAM-MSO(1)) and MSO(2) to the surface of GO through strong non-covalent bonding forces. Upon the addition of Hg(2+), the formation of the T-Hg(2+)-T configuration desorbed the FAM-MSO(1) and MSO(2) from the surface of GO, resulting in a restoration of the fluorescence of FAM-MSO(1). Using the specific mispairing of T-Hg(2+)-T and the changes in fluorescent signals in solutions, quantitative analysis of Hg(2+) could be performed.
  
  
  RESULTS
  The average thickness of the prepared GO sheets was only 1.4 nm. For the Hg(2+) nanobiosensor, the optimum concentrations of FAM-MSO(1) and MSO(2) were both 1 µmol/L, the optimum volume of 0.5 g/L GO was 5 µL, and the limit of detection was 10 pmol/L; it had low cross-reactivity with 10 other kinds of non-specific metal ions; the fluorescence recovery efficiency was up to 65% in the re-determination of Hg(2+) after addition of Na(2)S(2)O(3).
  
  
  CONCLUSIONS
  The MSO/GO-based nanobiosensor is convenient to operate, highly sensitive, highly specific, highly accurate, and reusable. It can be applied to determine trace amount of Hg(2+) in aqueous solutions.
authors.affiliation: Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine, Wenzhou Medical Univesity, Wenzhou, Zhejiang Province 325035, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Sun
authors.forename: Jue
authors.initials: J
authors.lastname: He
authors.forename: Xu-wu
authors.initials: XW
authors.lastname: Xiang
authors.forename: Xiao-lan
authors.initials: XL
authors.lastname: Hong
authors.forename: Xiao-yan
authors.initials: XY
authors.lastname: Yao
authors.forename: Lin-zhi
authors.initials: LZ
authors.lastname: Zhang
authors.forename: Yi-yun
authors.initials: YY
authors.lastname: Wang
authors.forename: Yan-ne
authors.initials: YN
authors.lastname: Xie
authors.forename: Wen-he
authors.initials: WH
authors.lastname: Wu
authors.forename: Jian-xin
authors.initials: JX
authors.lastname: Lu
mesh_terms: D015374:Biosensing Techniques; D005470:Fluorometry; D006108:Graphite; D008628:Mercury / Q000032:analysis*; D036103:Nanotechnology; D015345:Oligonucleotide Probes; D014867:Water
chemical_list: D015345:Oligonucleotide Probes; D014867:Water; D006108:Graphite; D008628:Mercury