Trapping and extraction of target DNA molecules using periodically crossed electrophoresis in the micropillar array

This paper presents a DNA (Deoxyribose Nucleic Acid) extractor based on an electrophoresis using periodically crossed electric fields in a micropillar array. The DNA extractor, having nanometer entropic barriers and micropillar array, was fabricated by micromachining processes. Under the crossed electric field, the DNA molecules, whose reorientation time is longer than the period of the crossed field, are trapped in the micropillar array. We applied the electric fields, crossed at 120°, to the DNA molecules in the micropillar array distributed in 120° direction. Three different DNA, including λ, micrococcus and T4 show reorientation times of 4.80 ± 0.44sec, 7.12 ± 0.75sec, and 9.71 ± 0.30sec for λ DNA(48.5 kbp), micrococcus DNA (115 kbp), and T4 DNA (169.8 kbp), respectively at E=5V/0.8cm. In the fabricated DNA extractor, T4 DNA cannot come out of the micropillar array for the crossed electric field of 5V/0.8cm at a 10 second interval. We have demonstrated that the present DNA extractor separates DNA molecules longer than a critical value, which can be adjusted by the magnitude and the period of the electric field across the micropillar array.