Measurements of Nonlinear Electrical Impedances by Virtue of Induced Conformational Changes in DNAs
Takatoki Yamamoto*, Sangwook Lee**, and Teruo Fujii**
*Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 135-8550, Japan
**Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba Meguro-ku Tokyo, 153-8505, Japan
A method for label-free electrical impedance sensing of DNA is proposed, and experimentally demonstrated using a micro Electrical Impedance Spectroscopy (µ- EIS) device. The method features not only the detection of DNA without any labelling, but also the control of the conformation that would enhance the electrical impedance signal. In order to conduct semiautomated measurements controlled by an external PC, a microfluidic chip made of a silicone elastomer of polydimethylsiloxane (PDMS), a measurement chip embedded with micro-electrodes, and a micropump chip are fully integrated in the µ-EIS device. The µ-EIS device is capable of detecting DNA concentrations of a few nM in aqueous solution of a few pL in volume by virtue of the conformation-enhanced nonlinear impedance response. As a first demonstration of conformational-change-induced DNA analysis, the frequency and the electric field strength dependence of various lengths of DNA are evaluated.
-  J. West, M. Becker, S. Tombrink, and A. Manz, “Micro Total Analysis Systems: Latest Achievements,” Analytical Chemistry, Vol.80, No.12, pp. 4403-4419, 2008.
-  P. G. Righetti, C. Gelfi, and M. R. D’Acunto, “Recent progress in DNA analysis by capillary electrophoresis,” Electrophoresis, Vol.23, No.10, pp. 1361-74, 2002.
-  E. Katz and I. Willner, “Probing Biomolecular Interactions at Conductive and Semiconductive Surfaces by Impedance Spectroscopy: Routes to Impedimetric Immunosensors, DNA-Sensors, and Enzyme Biosensors,” Electroanalysis, Vol.15, No.11, pp. 913-947, 2003.
-  J. Wang, Nucleic Acids Research, “From DNA biosensors to gene chips,” Vol.28, No.16, pp. 3011-3016, 2000.
-  H. P. Schwan, “Dielectric spectroscopy of biological materials and field interactions: the connection with Gerhard Schwarz,” Biophysical Chemistry, Vol.85, No.2-3, pp. 273-278, 2000.
-  H. P. Schwan, “The practical success of impedance techniques from an historical perspectives,” Ann. NY Acad. Sci., Vol.873 (Electrical Bioimpedance Methods: Applications to Medicine and Biotechnology), pp. 1-12, 1999.
-  S. Takashima, “Electrical properties of biopolymers and membranes,” A. Hilger: Bristol, Philadelphia, 1989.
-  T. Yamamoto and F. Teruo, “A MICROFABRICATION USING VACUUM ULTRAVIOLET LIGHT FOR µ-TAS APPLICATIONS,” Proc. of µ-TAS 2004, pp 133-135, 2004.
-  B. M. Olivera, P. Baine, and N. Davidson, “Electrophoresis of the nucleic acids,” Biopolymers, Vol.2, pp. 245-257, 1964,
-  M. Washizu and O. Kurosawa, “Electrostatic manipulation of DNA in microfabricated structures,” IEE Trans. on Industry Applications, Vol.26, No.6, pp. 1165-1172, 1990.
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