Electrical Evaluation of DNA Stretched and Immobilized Between Triangular-Shaped Electrodes
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.