Positioning of extended individual DNA molecules on electrodes by non-uniform AC electric fields

Recent developments in the analysis and the application of DNA often require the stretching of individual DNA molecules to specific surfaces. We propose and demonstrate a method for the positioning of unmodified extended DNA molecules. A local microscopic circular flow is created by a non-uniform AC field and utilized to stretch the λ-DNA on a gold surface or between gold electrodes. The electrical-field amplitude and frequency responses of DNA motion are studied. The method can be applied to position the DNA with accuracy on a microscopic scale while requiring no modification of the DNA for terminal binding. With a diluted DNA solution, the number of DNA molecules across the electrodes is controllable and the positioning of a single extended DNA across electrodes is achievable.