Echinomycin and cobalt-phenanthroline as redox indicators of DNA hybridization at gold electrodes

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Karadeniz H., Gulmez B., Erdem A., Jelen F., Ozsoz M., Palecek E.

FRONTIERS IN BIOSCIENCE-LANDMARK, vol.11, pp.1870-1877, 2006 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 11
  • Publication Date: 2006
  • Doi Number: 10.2741/1930
  • Page Numbers: pp.1870-1877


A bis-intercalator echinomycin (ECHI) and a simple intercalator [Co(phen)(3)](3+) were used as a novel electrochemical redox indicators to detect DNA hybridization at gold electrodes (AuE). In order to minimize the nonspecific adsorption of oligonucleotides (ODN), the thiol-derivatized oligonucleotides were immobilized onto AuE in the first step, and the exposition of AuE to 6-mercapto-1-hexanol (MCH) followed in the second step of this procedure. In this arrangement good reproducibility and discrimination between single-stranded (ss) probe and double-stranded (ds) hybrid DNA were obtained. While both redox indicators showed a good ability to discriminate between the ss probe and ds hybrid DNA, the signals of ECHI were by an order of maginitude higher than those of [Co(phen)(3)](3+) in a good agreement with stronger DNA binding by the bis-intercalator as compared to the simple intercalator. In addition, DNA single-base mismatch (DNA point mutation) was easily detected by means of ECHI.