title: Surface-modified poly(methyl methacrylate) capillary electrophoresis microchips for protein and peptide analysis.
abstract: Polymeric materials have emerged as appealing alternatives to conventional inorganic substrates for the fabrication of microscale analytical systems; however, native polymeric surfaces typically require covalent modification to ensure optimum biocompatibility. 2-Bromoisobutyryl bromide was immobilized on poly(methyl methacrylate) (PMMA) substrates activated using an oxygen plasma. Atom-transfer radical polymerization was then performed to graft poly(ethylene glycol) (PEG) on the PMMA surface. PMMA microcapillary electrophoresis (muCE) devices made with the covalently modified surfaces exhibited substantially reduced electroosmotic flow and nonspecific adsorption of proteins on microchannel surfaces. Experiments using fluorescein isothiocyanate-conjugated bovine serum albumin indicated that both column efficiency and migration time reproducibility were 1 order of magnitude better with derivatized compared to untreated PMMA muCE chips. Fast, reproducible, and efficient separations of proteins and peptides were demonstrated using the PEG-grafted PMMA muCE chips. All analyses were completed in less than 60 s, and separation efficiencies as high as 5.2 x10(4) plates for a 3.5-cm-long separation channel were obtained. These results demonstrate the general applicability of surface-grafted PMMA microdevices for a broad range of protein analyses.
authors.affiliation: Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602-5700, USA.
authors.forename: Jikun
authors.initials: J
authors.lastname: Liu
authors.forename: Tao
authors.initials: T
authors.lastname: Pan
authors.forename: Adam T
authors.initials: AT
authors.lastname: Woolley
authors.forename: Milton L
authors.initials: ML
authors.lastname: Lee
mesh_terms: D000818:Animals; D002417:Cattle; D004563:Electrochemistry; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods; D007328:Insulin / Q000032:analysis*; D056656:Lab-On-A-Chip Devices; D046208:Microchip Analytical Procedures / Q000379:methods*; D015394:Molecular Structure; D009995:Osmosis; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012710:Serum Albumin, Bovine / Q000032:analysis*; D013499:Surface Properties; D013997:Time Factors
chemical_list: D007328:Insulin; D012710:Serum Albumin, Bovine; D019904:Polymethyl Methacrylate