title: Separations in poly(dimethylsiloxane) microchips coated with supported bilayer membranes.
abstract: Hybrid microchannels composed of poly(dimethylsiloxane) and glass were coated with supported bilayer membranes (SBMs) by the process of vesicle fusion. The electroosmotic mobility (mu(eo)) of zwitterionic, positively charged, and negatively charged phospholipid membranes was measured over a 4 h time to evaluate the stability of the coatings in an electric field. Coated microchips with a simple cross design were used to separate the fluorescent dyes fluorescein and Oregon Green. Migration time reproducibility was better than 5% RSD over 70 min of continuous separations. Separation of Oregon Green and fluorescein in channels coated with zwitterionic phosphatidylcholine (PC) membranes yielded efficiencies of 611,000 and 499,000 plates/m and a resolution of 2.4 within 2 s. Both zwitterionic and negatively charged membranes were used to separate peptide substrates from their phosphorylated analogues with efficiencies of 200,000-400,000 plates/m. Notably, separations of fluorescently labeled ABL substrate peptide from its phosphorylated counterpart were achieved using a high-salt physiological buffer with near-baseline resolution in 10 s. PC-coated devices were used to successfully separate enhanced green fluorescent protein (eGFP) from a fusion protein (eGFP-Crakl) with an efficiency of 358,000 and 278,000 plates/m respectively in less than 12 s. These SBM-based coatings may enable the separation of a broad range of analytes and may be ideal in biological applications for microfluidics.
authors.affiliation: Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
authors.forename: K Scott
authors.initials: KS
authors.lastname: Phillips
authors.forename: Sumith
authors.initials: S
authors.lastname: Kottegoda
authors.forename: Kyung Mo
authors.initials: KM
authors.lastname: Kang
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Sims
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Allbritton
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D046209:Electrophoresis, Microchip; D005898:Glass / Q000737:chemistry; D049452:Green Fluorescent Proteins / Q000302:isolation & purification*; D006801:Humans; D020014:K562 Cells; D008051:Lipid Bilayers; D010446:Peptide Fragments / Q000302:isolation & purification*; D010743:Phospholipids / Q000737:chemistry; D010766:Phosphorylation; D016315:Proto-Oncogene Proteins c-abl / Q000302:isolation & purification*; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification*
chemical_list: D004129:Dimethylpolysiloxanes; D008051:Lipid Bilayers; D010446:Peptide Fragments; D010743:Phospholipids; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D016315:Proto-Oncogene Proteins c-abl