title: Comparative stability studies of poly(2-methyl-2-oxazoline) and poly(ethylene glycol) brush coatings.
abstract: Non-fouling surfaces that resist non-specific adsorption of proteins, bacteria, and higher organisms are of particular interest in diverse applications ranging from marine coatings to diagnostic devices and biomedical implants. Poly(ethylene glycol) (PEG) is the most frequently used polymer to impart surfaces with such non-fouling properties. Nevertheless, limitations in PEG stability have stimulated research on alternative polymers that are potentially more stable than PEG. Among them, we previously investigated poly(2-methyl-2-oxazoline) (PMOXA), a peptidomimetic polymer, and found that PMOXA shows excellent anti-fouling properties. Here, we compare the stability of films self-assembled from graft copolymers exposing a dense brush layer of PEG and PMOXA side chains, respectively, in physiological and oxidative media. Before media exposure both film types prevented the adsorption of full serum proteins to below the detection limit of optical waveguide in situ measurements. Before and after media exposure for up to 2 weeks, the total film thickness, chemical composition, and total adsorbed mass of the films were quantified using variable angle spectroscopic ellipsometry (VASE), X-ray photoelectron spectroscopy (XPS), and optical waveguide lightmode spectroscopy (OWLS), respectively. We found (i) that PMOXA graft copolymer films were significantly more stable than PEG graft copolymer films and kept their protein-repellent properties under all investigated conditions and (ii) that film degradation was due to side chain degradation rather than due to copolymer desorption.
authors.affiliation: Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093, Zurich, Switzerland. bidhari.pidhatika@alumni.ethz.ch
authors.forename: Bidhari
authors.initials: B
authors.lastname: Pidhatika
authors.forename: Mathias
authors.initials: M
authors.lastname: Rodenstein
authors.forename: Yin
authors.initials: Y
authors.lastname: Chen
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Rakhmatullina
authors.forename: Andreas
authors.initials: A
authors.lastname: Mühlebach
authors.forename: Canet
authors.initials: C
authors.lastname: Acikgöz
authors.forename: Marcus
authors.initials: M
authors.lastname: Textor
authors.forename: Rupert
authors.initials: R
authors.lastname: Konradi
mesh_terms: D000327:Adsorption; D001798:Blood Proteins / Q000032:analysis; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D011073:Polyamines / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*
chemical_list: D001798:Blood Proteins; D020099:Coated Materials, Biocompatible; D011073:Polyamines; C117403:poly(2-methyl-2-oxazoline); D011092:Polyethylene Glycols