DNA-Modified Electrodes: Molecular Recognition and Electrochemical Response

Koji Nakano, Shinji Uchida, Yoshiharu Mitsuhashi, Yuji Fujita, Hiroaki Taira, Mizuo Maeda

Research output: Contribution to journalArticle

5 Citations (Scopus)


A biosensor for the detection of the compounds that bind to DNA is reported. A chemical derivatization of terminal phosphate ends of DNA double strands (ds) with 2-hydroxyethyl disulfide was made to immobilize DNA onto Au surfaces via chemisorption. By taking advantages of the redox couple-mediated artificial ion-channel principle, the DMA-modified electrode was successfully applied for a bioaffinity sensor. For example, cyclic voltammograms (CV) of ferrocyanide/ferricyanide couple with the DNA-modified electrode gave the redox wave due to the reversible electrode reaction. The CV peak currents were significantly enhanced on adding quinacrine. The peak currents showed almost a linear relationship with the concentration of quinacrine in the range of 10-7 - 5 × 10-7 M, and then saturated beyond the concentration of 8 × 10-7 M. CV responses toward a variety of DNA-binding substrates including quinacrine, acridine orange, safranin, spermine and spermidine showed a reasonable selectivity order according to the DNA-binding affinity of these compounds, while the response was quite small for methyl viologen which binds to ds DNAs through a nonspecific electrostatic interaction. The sensitivity was diminished when the immobilized ds DNAs were heat-denatured. The voltammetric response is primarily due to a "titration" of the immobilized ds DNAs by DNA-binding molecules. Thus the response-concentration profile for quinacrine was analyzed by using the Langmuir's isotherm. The apparent binding constant thus obtained was 1.3 × 106 M-1 which agreed fairly well with that in literatures (1.5 × 106 M-1).

Original languageEnglish
Pages (from-to)34-45
Number of pages12
JournalACS Symposium Series
Publication statusPublished - Jan 1 1998

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)

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