title: Thiol surface functionalization via continuous phase plasma polymerization of allyl mercaptan, with subsequent maleimide-linked conjugation of collagen.
abstract: Thiol groups can undergo a large variety of chemical reactions and are used in solution phase to conjugate many bioactive molecules. Previous research on solid substrates with continuous phase glow discharge polymerization of thiol-containing monomers may have been compromised by oxidation. Thiol surface functionalization via glow discharge polymerization has been reported as requiring pulsing. Herein, continuous phase glow discharge polymerization of allyl mercaptan (2-propene-1-thiol) was used to generate significant densities of thiol groups on a mixed macrodiol polyurethane and tantalum. Three general classes of chemistry are used to conjugate proteins to thiol groups, with maleimide linkers being used most commonly. Here the pH specificity of maleimide reactions was used effectively to conjugate surface-bound thiol groups to amine groups in collagen. XPS demonstrated surface-bound thiol groups without evidence of oxidation, along with the subsequent presence of maleimide and collagen. Glow discharge reactor parameters were optimized by testing the resistance of bound collagen to degradation by 8 M urea. The nature of the chemical bonding of collagen to surface thiol groups was effectively assessed by colorimetric assay (ELISA) of residual collagen after incubation in 8 M urea over 8 days and after incubation with keratinocytes over 15 days. The facile creation of useable solid-supported thiol groups via continuous phase glow discharge polymerization of allyl mercaptan opens a route for attaching a vast array of bioactive molecules. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1940-1948, 2017.
authors.affiliation: Department of Surgery, St Vincent's Hospital, University of Melbourne, Victoria, Australia.|Barwon Biomedical Research, University Hospital Geelong, Victoria, Australia.|Commonwealth Scientific and Industrial Research Organisation (CSIRO), Victoria, Australia.|Institute for Frontier Materials, Deakin University, Victoria, Australia.
authors.forename: Gil D
authors.identifier: http://orcid.org/0000-0003-3263-7754
authors.initials: GD
authors.lastname: Stynes
authors.affiliation: Commonwealth Scientific and Industrial Research Organisation (CSIRO), Victoria, Australia.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Gengenbach
authors.affiliation: Queen Elizabeth Hospital, The University of Adelaide, South Australia, Australia.
authors.forename: George K
authors.initials: GK
authors.lastname: Kiroff
authors.affiliation: Department of Surgery, St Vincent's Hospital, University of Melbourne, Victoria, Australia.
authors.forename: Wayne A
authors.initials: WA
authors.lastname: Morrison
authors.affiliation: Institute for Frontier Materials, Deakin University, Victoria, Australia.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Kirkland
mesh_terms: D003094:Collagen / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry*; D008301:Maleimides / Q000737:chemistry*; D058626:Plasma Gases / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013499:Surface Properties; D014508:Urea / Q000737:chemistry
chemical_list: D003432:Cross-Linking Reagents; D008301:Maleimides; D058626:Plasma Gases; D013438:Sulfhydryl Compounds; C043592:maleimide; D014508:Urea; D003094:Collagen
keywords: biological activity; plasma chemistry; protein engineering; surface analysis; thiol