title: Protein, cell and bacterial response to atmospheric pressure plasma grafted hyaluronic acid on poly(methylmethacrylate).
abstract: Hyaluronic acid (HA) has been immobilised on poly(methyl methacrylate) (PMMA) surfaces using a novel dielectric barrier discharge (DBD) plasma process for the purposes of repelling protein, cellular and bacterial adhesion in the context of improving the performance of ophthalmic devices. Grafting was achieved by the following steps: (1) treatment of the PMMA with a DBD plasma operating at atmospheric pressure, (2) amine functionalisation of the activated polymer surface by exposure to a 3-aminopropyltrimethoxysilane (APTMS) linker molecule and (3) reaction of HA with the surface bound amine. The mechanism and effectiveness of the grafting process was verified by surface analysis. XPS data indicates that the APTMS linker molecule binds to PMMA via the Si-O chemistry and has the required pendant amine moiety. The carboxylic acid moiety on HA then binds with this -NH2 group via standard carbodiimide chemistry. ToF-SIMS confirms the presence of a coherent HA layer the microstructure of which is verified by AFM. The plasma grafted HA coating surfaces showed a pronounced decrease in protein and cellular adhesion when tested with bovine serum albumin and human corneal epithelial cells, respectively. The ability of these coatings to resist bacterial adhesion was established using Staphylococcus aureus NTC8325. Interestingly, the coatings did not repel bacterial adhesion, indicating that the mechanism of adhesion of bacterial cells is different to that for the surface interactions of mammalian cells. It is proposed that this difference is a consequence of the specific HA conformation that occurs under the conditions employed here. Hence, it is apparent that the microstructure/architecture of the HA coatings is an important factor in fabricating surfaces intended to repel proteins, mammalian and bacterial cells.
authors.affiliation: Centre for Materials and Structures, University of Liverpool, Brownlow Hill, Liverpool, L69 3GH, UK. r.dsa@liverpool.ac.uk.|Nanotechnology and Integrated Bio-Engineering Centre (NIBEC), University of Ulster, Shore Road, Newtownabbey, BT37 0QB, UK. r.dsa@liverpool.ac.uk.
authors.forename: Raechelle A
authors.initials: RA
authors.lastname: D'Sa
authors.affiliation: Nanotechnology and Integrated Bio-Engineering Centre (NIBEC), University of Ulster, Shore Road, Newtownabbey, BT37 0QB, UK.
authors.forename: Jog
authors.initials: J
authors.lastname: Raj
authors.affiliation: Nanotechnology and Integrated Bio-Engineering Centre (NIBEC), University of Ulster, Shore Road, Newtownabbey, BT37 0QB, UK.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Dickinson
authors.affiliation: Biomedical Sciences Research Institute, School of Heath Sciences, University of Ulster, Shore Road, Newtownabbey, BT37 0QB, UK.
authors.forename: M Ann S
authors.initials: MA
authors.lastname: McMahon
authors.affiliation: Biomedical Sciences Research Institute, School of Heath Sciences, University of Ulster, Shore Road, Newtownabbey, BT37 0QB, UK.
authors.forename: David A
authors.initials: DA
authors.lastname: McDowell
authors.affiliation: Nanotechnology and Integrated Bio-Engineering Centre (NIBEC), University of Ulster, Shore Road, Newtownabbey, BT37 0QB, UK.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Meenan
mesh_terms: D001274:Atmospheric Pressure; D002461:Cell Line, Transformed; D006801:Humans; D006820:Hyaluronic Acid / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D056951:Photoelectron Spectroscopy; D058626:Plasma Gases; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D011506:Proteins / Q000378:metabolism; D013211:Staphylococcus aureus / Q000502:physiology*; D013499:Surface Properties
chemical_list: D058626:Plasma Gases; D011506:Proteins; D006820:Hyaluronic Acid; D019904:Polymethyl Methacrylate