Multistep liquid-phase lithography for fast prototyping of microfluidic free-flow-electrophoresis chips
We present a fast and versatile method to produce functional micro free-flow electrophoresis chips. Microfluidic structures were generated between two glass slides applying multistep liquid-phase lithography, omitting troublesome bonding steps or cost-intensive master structures. Utilizing a novel spacer-less approach with the photodefinable polymer polyethyleneglycol dimethacrylate (PEG-DA), microfluidic devices with hydrophilic channels of only 25 μm in height were generated. The microfluidic chips feature ion-permeable segregation walls between the electrode channels and the separation bed and hydrophilic surfaces. The performance of the chip is demonstrated by free-flow electrophoretic separation of fluorescent xanthene dyes and fluorescently labeled amino acids.
KeywordsCapillary electrophoresis/electrophoresis Microfluidics Microfabrication Free-flow electrophoresis Lab-on-a-chip
S.J. is supported by the European Social Fund (ESF # 080938819) and S.N. by the Deutsche Forschungsgemeinschaft (DFG). The assistance of B. Kohlstrunk, Prof. J. A. Käs (mask aligner) and G. Ramm, Prof. M. Grundmann (surface profiles) from the Physics Department, University of Leipzig, is gratefully acknowledged.
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