title: Automated coating procedures to produce poly(ethylene glycol) brushes in fused-silica capillaries.
abstract: Many bioanalytical methods rely on electrophoretic separation of structurally labile and surface active biomolecules such as proteins and peptides. Often poor separation efficiency is due to surface adsorption processes leading to protein denaturation and surface fouling in the separation channel. Flexible and reliable approaches for preventing unwanted protein adsorption in separation science are thus in high demand. We therefore present new coating approaches based on an automated in-capillary surface-initiated atom transfer radical polymerization process (covalent coating) as well as by electrostatically adsorbing a presynthesized polymer leading to functionalized molecular brushes. The electroosmotic flow was measured following each step of the covalent coating procedure providing a detailed characterization and quality control. Both approaches resulted in good fouling resistance against the four model proteins cytochrome c, myoglobin, ovalbumin, and human serum albumin in the pH range 3.4-8.4. Further, even samples containing 10% v/v plasma derived from human blood did not show signs of adsorbing to the coated capillaries. The covalent as well as the electrostatically adsorbed coating were both found to be stable and provided almost complete suppression of the electroosmotic flow in the pH range 3.4-8.4. The coating procedures may easily be integrated in fully automated capillary electrophoresis methodologies.
authors.affiliation: Department of Pharmacy, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Nicklas N
authors.initials: NN
authors.lastname: Poulsen
authors.affiliation: Department of Pharmacy, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Jesper
authors.initials: J
authors.lastname: Østergaard
authors.affiliation: Department of Pharmacy, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Nickolaj J
authors.initials: NJ
authors.lastname: Petersen
authors.affiliation: Department of Chemistry, Aarhus University, Aarhus, Denmark.|Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark.|Carbon Dioxide Activation Center, Aarhus University, Aarhus, Denmark.
authors.forename: Kim
authors.initials: K
authors.lastname: Daasbjerg
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark.|Biological and Chemical Engineering Division, Aarhus University, Aarhus N, Denmark.
authors.forename: Joseph
authors.initials: J
authors.lastname: Iruthayaraj
authors.affiliation: Department of Chemistry, Surface and Corrosion Science, School of Chemical Sciences and Engineering, KTH Royal Institute of Technology, Stockholm, Sweden.
authors.forename: Andra
authors.initials: A
authors.lastname: Dedinaite
authors.affiliation: Department of Polymer Chemistry, Vilnius University, Vilnius, Lithuania.
authors.forename: Ricardas
authors.initials: R
authors.lastname: Makuska
authors.affiliation: Department of Pharmacy, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Jensen
mesh_terms: D000327:Adsorption; D001774:Blood Chemical Analysis / Q000295:instrumentation / Q000379:methods*; D045304:Cytochromes c / Q000097:blood; D019075:Electrophoresis, Capillary / Q000295:instrumentation*; D006801:Humans; D009211:Myoglobin / Q000097:blood; D010047:Ovalbumin / Q000097:blood; D011092:Polyethylene Glycols / Q000737:chemistry*; D011506:Proteins / Q000378:metabolism; D012709:Serum Albumin / Q000032:analysis; D012822:Silicon Dioxide / Q000737:chemistry
chemical_list: D009211:Myoglobin; D011506:Proteins; D012709:Serum Albumin; D011092:Polyethylene Glycols; D012822:Silicon Dioxide; D010047:Ovalbumin; D045304:Cytochromes c
keywords: adsorption; automation; capillary electrophoresis; molecular brushes