Electrical frequency dependent characterization of DNA hybridization

Marin Gheorghe, Anthony Guiseppi-Elie

Research output: Contribution to journalArticlepeer-review

52 Scopus citations


The hybridization of oligomeric DNA was investigated using the frequency dependent techniques of electrochemical impedance spectroscopy (EIS) and quartz crystal microgravimetry (QCM). Synthetic 5′-amino terminated single stranded oligonucleotides (ssDNA) were attached to the exposed glass surface between the digits of microlithographically fabricated interdigitated microsensor electrodes using 3-glycidoxypropyl-trimethoxysilane. Similar ssDNA immobilization was achieved to the surface of the gold driving electrodes of AT-cut quartz QCM crystals using 3-mercaptopropyl-trimethoxysilane. Significant changes in electrochemical impedance values (both real and imaginary components) (11% increase in impedance modulus at 120 Hz) and resonant frequency values (0.004% decrease) were detected as a consequence of hybridization of the bound ssDNA upon exposure to its complement under hybridization conditions. Non-complementary (random) sequence sowed a modest decrease in impedance and a non-detectable change in resonant frequency. The possibility to detect the binding state of DNA in the vicinity of an electrode, without a direct connection between the measurement electrode and the DNA, has been demonstrated. The potential for development of label-free, low density DNA microarrays is demonstrated and is being pursued.

Original languageEnglish (US)
Pages (from-to)95-102
Number of pages8
JournalBiosensors and Bioelectronics
Issue number2
StatePublished - Nov 15 2003


  • DNA
  • DNA hybridization
  • Electrochemical impedance spectroscopy
  • Microarrays
  • Oligonucleotides
  • Quartz crystal microbalance
  • Silanes

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry


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