Self-focusing DNA separation chips using micropillar array with nonuniformly distributed asymmetric electric fields

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 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. (C) 2006 Elsevier B.V. All rights reserved.