Authors: H. Dalir, T. Nisisako, T. Endo, Y. Yanagida, T. Hatsuzawa
Affilation: Tokyo Institute of Technology, Japan
Pages: 312 - 315
Keywords: DNA manipulation, DNA stretching, high frequency measurements, gap geometry, Edge roughness
The manipulation of molecules is a crucial prerequisite for the emerging field of molecular nanobiotechnology. This paper reports measurements that characterize the immobilization of 48 kilobase-pair lambda DNA onto lifted-off microelectrodes by high-voltage and high-frequency dielectrophoresis. Measurements of voltage- and frequency-dependent immobilization of DNA onto microelectrodes by dielectrophoresis show significant reduction in the response as the frequency increases from 200 kHz to 1 MHz or decreases from 200 kHz to 100 kHz and is maximized as the electric field is near to 0.4 Vp-p/m. We find that the immobilization and elongation of the DNA molecules is restricted by the geometry of the gap, and that by decreasing the electrode gap size, the DNA molecules have less chance for both immobilization and stretching. Further, we discuss two potential mechanisms for both immobilization and elongation of DNA molecules based on the induced electrothermal fluid flow type and required immobilization time. The produced electrodes with both random microscopic peaks and modified smooth edges are utilized to show the effect of electrode edge roughness. The results imply that more DNA molecules can be immobilized by microelectrodes having rough edges. The experimental results are discussed with suggested improvements to microelectrodes geometry and dimensions.