title: Rapid protein separations in ultra-short microchannels: microchip sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing.
abstract: We have developed novel protein gel electrophoresis techniques, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing (IEF) in short microchannels (approximately millimeters) that take less than a minute. A photopatterning technique was used to cast in situ crosslinked polyacrylamide gel in a microchannel to perform SDS-PAGE. A fluorescent protein marker sample (Mr range of 20,000-200,000) was separated in less than 30 s in less than 2 mm of channel length. Crosslinked polyacrylamide gel, patterned in channels using UV light, provides higher sieving power and sample stacking effect, therefore yielding faster and higher-resolution separation in a chip. IEF of proteins was also achieved in a microchannel, and several proteins were focussed within tens of seconds in mm-length channels. As resolution in IEF is independent of separation distance, focusing in ultra-short channels results in not only faster separation but also more concentrated bands potentially allowing detection of low-concentration species.
authors.affiliation: Sandia National Laboratories, Livermore, CA, USA. jyhan@mit.edu
authors.forename: Jongyoon
authors.initials: J
authors.lastname: Han
authors.forename: Anup K
authors.initials: AK
authors.lastname: Singh
mesh_terms: D004591:Electrophoresis, Polyacrylamide Gel / Q000295:instrumentation* / Q000379:methods*; D005456:Fluorescent Dyes; D007202:Indicators and Reagents; D007525:Isoelectric Focusing / Q000379:methods*; D008838:Microcomputers; D008970:Molecular Weight; D036103:Nanotechnology; D011506:Proteins / Q000302:isolation & purification*
chemical_list: D005456:Fluorescent Dyes; D007202:Indicators and Reagents; D011506:Proteins