Abstract
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 language | English (US) |
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Pages (from-to) | 95-102 |
Number of pages | 8 |
Journal | Biosensors and Bioelectronics |
Volume | 19 |
Issue number | 2 |
DOIs | |
State | Published - Nov 15 2003 |
Keywords
- DNA
- DNA hybridization
- Electrochemical impedance spectroscopy
- Microarrays
- Oligonucleotides
- Quartz crystal microbalance
- Silanes
ASJC Scopus subject areas
- Biotechnology
- Biophysics
- Biomedical Engineering
- Electrochemistry