As a step toward applications for biosensors, we characterized the electrical properties of λDNA molecules via their current–voltage characteristics and complex impedance plots. λDNA molecules were introduced to a microfluidic device using a microchannel (depth, 50 μm; width, 500 μm; length, 10 mm) and electrostatically stretched and immobilized in the 14-μm gap between two triangular-shaped microlithographed aluminum electrodes by applying an alternating voltage of 1 MHz and 20 Vp–p. The aligned λDNA showed nonlinear current–voltage characteristics. From the complex impedance plots of the λDNA molecules, an equivalent circuit was obtained as a series connection of two resistance–capacitance parallel circuits. Finally, we demonstrated that the electrical characteristics of the λDNA between the electrodes varied with the number of immobilized λDNA molecules.
DNA impedance equivalent circuit electrostatic orientation
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This work was partially supported by a Grant-in-Aid for Young Scientists (Grant No.: JP18K13769) and a Grant-in-Aid for Challenging Exploratory Research (Grant No.: JP16K14281) from JSPS. The authors gratefully thank Dr. Masanori Eguchi of the National Institute of Technology, Kure College for his help with electron-beam lithography exposure and I–V measurements. We are grateful to Prof. Seiichi Suzuki of Seikei University for his help with fluorescence observation.