title: Reactive thin polymer films as platforms for the immobilization of biomolecules.
abstract: Spin-coated thin films of poly(N-hydroxysuccinimidyl methacrylate) (PNHSMA) on oxidized silicon and gold surfaces were investigated as reactive layers for obtaining platforms for biomolecule immobilization with high molecular loading. The surface reactivity of PNHSMA films in coupling reactions with various primary amines, including amine-terminated poly(ethylene glycol) (PEG-NH2) and fluoresceinamine, was determined by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), fluorescence microscopy, and ellipsometry measurements, respectively. The rate constants of PEG-NH2 attachment on the PNHSMA films were found to be significantly increased compared to the coupling on self-assembled monolayers (SAMs) of 11,11'-dithiobis(N-hydroxysuccinimidylundecanoate) (NHS-C10) on gold under the same conditions. More significantly, the PEG loading observed was about 3 times higher for the polymer thin films. These data indicate that the coupling reactions are not limited to the very surface of the polymer films, but proceed into the near-surface regions of the films. PNHSMA films were shown to be stable in contact with aqueous buffer; the swelling analysis, as performed by atomic force microscopy (AFM), indicated a film thickness independent swelling of approximately 2 nm. An increased loading was also observed by surface plasmon resonance for the covalent immobilization of amino-functionalized probe DNA. Hybridization of fluorescently labeled target DNA was successfully detected by fluorescence microscopy and surface plasmon resonance enhanced fluorescence spectroscopy (SPFS), thereby demonstrating that thin films of PNHSMA comprise an attractive and simple platform for the immobilization of biomolecules with high densities.
authors.affiliation: Department of Materials Science and Technology of Polymers, MESA Institute for Nanotechnology and Faculty of Science and Technology, University of Twente, P. O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: Chuan Liang
authors.initials: CL
authors.lastname: Feng
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Zhang
authors.forename: Renate
authors.initials: R
authors.lastname: Förch
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Knoll
authors.forename: G Julius
authors.initials: GJ
authors.lastname: Vancso
authors.forename: Holger
authors.initials: H
authors.lastname: Schönherr
mesh_terms: D000327:Adsorption; D000588:Amines / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry*; D001703:Biophysics / Q000379:methods*; D004247:DNA / Q000737:chemistry*; D005227:Fatty Acids / Q000737:chemistry*; D019793:Fluorescein / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D007700:Kinetics; D046911:Macromolecular Substances / Q000737:chemistry*; D008689:Methacrylates / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008856:Microscopy, Fluorescence; D008956:Models, Chemical; D008970:Molecular Weight; D009040:Motion Pictures; D036103:Nanotechnology; D009693:Nucleic Acid Hybridization; D010100:Oxygen / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D013386:Succinates / Q000737:chemistry*; D020349:Surface Plasmon Resonance; D013499:Surface Properties; D013997:Time Factors
chemical_list: C507589:11,11'-dithiobis(N-hydroxysuccinimidylundecanoate); D000588:Amines; D001672:Biocompatible Materials; D005227:Fatty Acids; D046911:Macromolecular Substances; D008689:Methacrylates; D011108:Polymers; D013386:Succinates; C507590:poly(N-hydroxysuccinimidyl methacrylate); D011092:Polyethylene Glycols; D006046:Gold; D004247:DNA; D010100:Oxygen; D019793:Fluorescein