DNA Self-Focusing Chips Using 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 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.