Verification of the effect of electric field strength and gradient on the elongation of DNA molecules using the confinement effect

Abstract

For reading out genomic information from a single molecule of DNA, it is required to establish a DNA extension method that stretches a DNA molecule existing in a random coil state in a solution. To achieve highly stretched DNA molecules, we utilized and experimentally verified the effect of hydrodynamic drag force and electric field gradient in addition to the effect of nano-confinement; channels heights smaller than the persistence length of DNA molecules. In our experimental results, we revealed that the higher the migration velocity, the higher the elongation rate of DNA molecules. Moreover, by comparing the elongation rate of molecules measured in rectangular and taper-shaped nanoslits, we were able to achieve a higher degree of elongation in the latter type, which had the electric field gradient.