title: PEGMA/MMA copolymer graftings: generation, protein resistance, and a hydrophobic domain.
abstract: We synthesized various graft copolymer films of poly(ethylene glycol) methacrylate (PEGMA) and methyl methacrylate (MMA) on silicon to examine the dependency of protein-surface interactions on grafting composition. We optimized atom transfer radical polymerizations to achieve film thicknesses from 25 to 100 nm depending on the monomer mole fractions, and analyzed the resulting surfaces by X-ray photoelectron spectroscopy (XPS), ellipsometry, contact angle measurements, and atomic force microscopy (AFM). As determined by XPS, the stoichiometric ratios of copolymer graftings correlated with the concentrations of provided monomer solutions. However, we found an unexpected and pronounced hydrophobic domain on copolymer films with a molar amount of 10-40% PEGMA, as indicated by advancing contact angles of up to 90 degrees . Nevertheless, a breakdown of the protein-repelling character was only observed for a fraction of 15% PEGMA and lower, far in the hydrophobic domain. Investigation of the structural basis of this exceptional wettability by high-resolution AFM demonstrated the independence of this property from morphological features.
authors.affiliation: Research Groups Chip-Based Peptide Libraries and Microenvironment of Tumor Cell Invasion, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany. V.Stadler@dkfz.de
authors.forename: Volker
authors.initials: V
authors.lastname: Stadler
authors.forename: Robert
authors.initials: R
authors.lastname: Kirmse
authors.forename: Mario
authors.initials: M
authors.lastname: Beyer
authors.forename: Frank
authors.initials: F
authors.lastname: Breitling
authors.forename: Thomas
authors.initials: T
authors.lastname: Ludwig
authors.forename: F Ralf
authors.initials: FR
authors.lastname: Bischoff
mesh_terms: D057927:Hydrophobic and Hydrophilic Interactions; D008689:Methacrylates / Q000737:chemistry*; D008768:Methylmethacrylates / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D015394:Molecular Structure; D011092:Polyethylene Glycols / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D008689:Methacrylates; D008768:Methylmethacrylates; D011506:Proteins; C524499:polyethylene glycol methacrylate; D011092:Polyethylene Glycols