Nafion film based nanofluidic device for concurrent DNA preconcentration and separation

This paper presents a Nafion film based micro-nanofluidic device for concurrent DNA preconcentration and separation. The principle of the device is based on: (a) ion concentration polarization phenomenon at the junction of the microchannel and the nanochannels in the Nafion film to form opposing electrophoretic and electroosmotic forces acting on the DNAs, combined with (b) end-labeled free solution electrophoresis to vary the charge-to-mass ratio for molecular differentiation. Extensive experiments were carried out to characterize the functionality of the device. Concurrent preconcentration and separation of a DNA mixture within 240s were successfully demonstrated, yielding concentration ratios up to 1,150X and separation resolution of 1.85. The effect of applied electric field on the concentration and separation performance was investigated. The device can be used as a key sample preparation element in conjunction with micro- or nanofluidic sensors to obtained microTAS functionality.