title: Biofunctionalized, ultrathin coatings of cross-linked star-shaped poly(ethylene oxide) allow reversible folding of immobilized proteins.
abstract: Dense, ultrathin networks of isocyanate terminated star-shaped poly(ethylene oxide) (PEO) molecules, cross-linked at their chain ends via urea groups, were shown to be extremely resistant to unspecific adsorption of proteins while at the same time suitable for easy biocompatible modification. Application by spin coating offers a simple procedure for the preparation of minimally interacting surfaces that are functionalized by suitable linker groups to immobilize proteins in their native conformations. These coatings form a versatile basis for biofunctional and biomimetic surfaces. We have demonstrated their advantageous properties by using single-molecule fluorescence microscopy to study immobilized proteins under destabilizing conditions. Biotinylated ribonuclease H (RNase H) was labeled with a fluorescence resonance energy transfer (FRET) pair of fluorescent dyes and attached to the surface by a biotin-streptavidin linkage. FRET analysis demonstrated completely reversible denaturation/renaturation behavior upon exposure of the surface-immobilized proteins to 6 M guanidinium chloride (GdmCl) followed by washing in buffer. A comparison with bovine serum albumin (BSA) coated surfaces and linear PEO brush surfaces yielded superior performance in terms of chemical stability, inertness and noninteracting nature of the star-polymer derived films.
authors.affiliation: Department of Macromolecular Chemistry and Organic Chemistry III, University of Ulm, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Groll
authors.forename: Elza V
authors.initials: EV
authors.lastname: Amirgoulova
authors.forename: Thomas
authors.initials: T
authors.lastname: Ameringer
authors.forename: Colin D
authors.initials: CD
authors.lastname: Heyes
authors.forename: Carlheinz
authors.initials: C
authors.lastname: Röcker
authors.forename: G Ulrich
authors.initials: GU
authors.lastname: Nienhaus
authors.forename: Martin
authors.initials: M
authors.lastname: Möller
mesh_terms: D040761:Biomimetic Materials / Q000138:chemical synthesis / Q000737:chemistry*; D005822:Genetic Vectors; D018625:Microscopy, Atomic Force; D010957:Plasmids; D011092:Polyethylene Glycols / Q000138:chemical synthesis / Q000737:chemistry*; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry; D011487:Protein Conformation; D017510:Protein Folding; D011506:Proteins / Q000737:chemistry; D016914:Ribonuclease H / Q000378:metabolism; D019809:Streptavidin / Q000378:metabolism; D013499:Surface Properties
chemical_list: D011108:Polymers; D011506:Proteins; D011092:Polyethylene Glycols; D019809:Streptavidin; D016914:Ribonuclease H; C078856:ribonuclease HI