title: Surface modification of glycidyl-containing poly(methyl methacrylate) microchips using surface-initiated atom-transfer radical polymerization.
abstract: Fabrication of microfluidic systems from polymeric materials is attractive because of simplicity and low cost. Unfortunately, the surfaces of many polymeric materials can adsorb biological samples. Therefore, it is necessary to modify their surfaces before these polymeric materials can be used for separation and analysis. Oftentimes it is difficult to modify polymeric surfaces because of their resistance to chemical reaction. Recently, we introduced a surface-reactive acrylic polymer, poly(glycidyl methacrylate-co-methyl methacrylate) (PGMAMMA), which can be modified easily and is suitable for fabrication of microfluidic devices. Epoxy groups on the surface can be activated by air plasma treatment, hydrolysis, or aminolysis. In this work, the resulting hydroxyl or amino groups were reacted with 2-bromoisobutylryl bromide to introduce an initiator for surface-initiated atom-transfer radical polymerization (SI-ATRP). Polyethylene glycol (PEG) layers grown on the surface using this method were uniform, hydrophilic, stable, and resistant to protein adsorption. Contact angle measurement and X-ray photoelectron spectroscopy (XPS) were used to characterize activated polymer surfaces, initiator-bound surfaces, and PEG-grafted surfaces. We obtained excellent capillary electrophoresis (CE) separations of proteins and peptides with the PEG-modified microchips. A separation efficiency of 4.4 x 10(4) plates for a 3.5 cm long separation channel was obtained.
authors.affiliation: Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602-5700, USA.
authors.forename: Xuefei
authors.initials: X
authors.lastname: Sun
authors.forename: Jikun
authors.initials: J
authors.lastname: Liu
authors.forename: Milton L
authors.initials: ML
authors.lastname: Lee
mesh_terms: D000588:Amines / Q000737:chemistry; D019075:Electrophoresis, Capillary; D004852:Epoxy Compounds / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D006842:Hydrocarbons, Brominated / Q000737:chemistry; D006868:Hydrolysis; D056656:Lab-On-A-Chip Devices; D008689:Methacrylates / Q000737:chemistry*; D046208:Microchip Analytical Procedures / Q000379:methods*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*; D011092:Polyethylene Glycols / Q000737:chemistry; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D013057:Spectrum Analysis; D013499:Surface Properties; D013997:Time Factors
chemical_list: D000588:Amines; D004852:Epoxy Compounds; D005609:Free Radicals; D006842:Hydrocarbons, Brominated; D008689:Methacrylates; D011092:Polyethylene Glycols; D019904:Polymethyl Methacrylate; C007870:glycidyl methacrylate