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This paper presents the experimental study to realize a DNA separation chip based on the self-focusing effect in a micropillar array. The present self-focusing chip redistributes DNA molecules within a specific area of micropillar arrays based on the size- and field-dependent nonlinearity of DNA drift velocity. Compared to conventional electrophoresis chips, the present self-focusing chip reduces a substantial amount of the separation channel length, the influence of sample starting location, and the necessity of time-consuming continuous monitoring process. We focus on the design of DNA self-focusing chips, with identifying the nonlinearity of DNA drift velocity using three different DNA molecules including λ DNA(48.5 kbp), micrococcus DNA(115 kbp), and T4 DNA(169.8 kbp) in microfabricated test chips. It is demonstrated that the present DNA self-focusing chips have potentials not only for the miniaturization of DNA analysis systems, but also for the tunable capability of the target DNA size to be separated, trapped and extracted.

This paper presents an integrated deoxyribose nucleic acid (DNA) trapping and extraction microchip based on the electrophoresis using periodically crossed electric fields in the micropillar array. The extraction microchip, integrated with a micropillar array, microchannels, nano-gap entropic barriers, loading and unloading windows, has been fabricated by a 3-mask microfabrication process. Using the electric field crossed at 120°, the microchip is designed to trap the DNA molecules, whose reorientation time is longer than the period of the crossed field, within the micropillars distributed at 60° direction. In the fabricated extraction microchip, three different DNA molecules, including λ DNA (48.5 kbp), micrococcus DNA (115 kbp) and T4 DNA (168.9 kbp) show the reorientation times of 4.80 ± 0.44 s, 7.12 ± 0.75 s and 9.71 ± 0.30 s, respectively, at the crossed electric field of 6.25 V/cm. Among three DNA molecules, T4 DNA could not come out of the micropillar array for the electric field of 6.25 V/cm crossed at the period of 10 s. We have demonstrated that the present DNA extraction microchip separates DNA molecules larger than a critical value, which can be adjusted by the period of the electric field across the micropillar array.

This paper presents the experimental study to realize a DNA separation chip based on the self-focusing effect in a microfabricated PDMS chip. The present self-focusing chip redistributes DNA molecules within a specific area based on the size- and field-dependent nonlinearity of DNA drift velocity. Compared to conventional electrophoresis chips, the present self-focusing chip offers the advantages of simple structure, short separation channel length, and starting-point independent DNA separation. We focus on the design of DNA self-focusing chips, with identifying the nonlinearity of DNA drift velocity using three different DNA molecules (11.1kbp, 15.6kbp, and 48.5kbp) in test chips. It is demonstrated that the present DNA self-focusing chips have potentials not only for the miniaturization of DNA analysis systems, but also for the tunable capability of the target DNA size to be separated, trapped and extracted.

This paper presents the first experimental study to realize a DNA separation chip based on the self-focusing effect in a micropillar array. The present self-focusing chip redistributes DNA molecules within a specific area of micropillar arrays based on the size- and field-dependent nonlinearity of DNA drift velocity. Compared to conventional electrophoresis chips, the present self-focusing chip reduces a substantial amount of the separation channel length, the influence of sample starting location, and the necessity of time-consuming continuous monitoring process. We focus on the design of DNA self-focusing chips, with identifying the nonlinearity of DNA drift velocity using three different DNA molecules including /spl lambda/ DNA (48.5 kbp), micrococcus DNA (115 kbp), and T4 DNA (169.8 kbp) in microfabricated test chips. It is demonstrated that the present DNA self-focusing chips have potentials not only for the miniaturization of DNA analysis systems, but also for the tunable capability of the target DNA size to be separated, trapped and extracted.

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/spl deg/, to the DNA molecules in the micropillar array distributed in 120/spl deg/ direction. Three different DNA, including /spl lambda/, micrococcus and T4 show reorientation times of 4.80 /spl plusmn/ 0.44sec, 7.12 /spl plusmn/ 0.75sec, and 9.71 /spl plusmn/ 0.30sec for /spl lambda/ 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.