A regenerative electrochemical sensor based on oligonucleotide for the selective determination of mercury(II)

Donghoon Han, Yang Rae Kim, Jeong Wook Oh, Tae Hyun Kim, Rakesh Kumar Mahajan, Jong Seung Kim, Hasuck Kim

Research output: Contribution to journalArticlepeer-review

118 Citations (Scopus)


We have developed a selective, sensitive, and re-usable electrochemical sensor for Hg2+ ion detection. This sensor is based on the Hg 2+-induced conformational change of a single-stranded DNA (ssDNA) which involves an electroactive, ferrocene-labeled DNA hairpin structure and provides strategically the selective binding of a thymine-thymine mismatch for the Hg2+ ion. The ferrocene-labeled DNA is self-assembled through S-Au bonding on a polycrystalline gold electrode surface and the surface blocked with 3-mercapto-1-propanol to form a mixed monolayer. The modified electrode showed a voltammetric signal due to a one-step redox reaction of the surface-confined ferrocenyl moiety. The 'signal-on' upon mercury binding could be attributed to a change in the conformation of ferrocene-labeled DNA from an open structure to a restricted hairpin structure. The differential pulse voltammetry (DPV) of the modified electrode showed a linear response of the ferrocene oxidation signal with increase of Hg2+ concentration in the range between 0.1 and 2 M with a detection limit of 0.1 M. The molecular beacon mercury(ii) ion sensor was amenable to regeneration by simply unfolding the ferrocene-labeled DNA in 10 M cysteine, and could be regenerated with no loss in signal gain upon subsequent mercury(ii) ion binding.

Original languageEnglish
Pages (from-to)1857-1862
Number of pages6
Issue number9
Publication statusPublished - 2009

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy
  • Electrochemistry


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