title: Poly(dimethyl siloxane) surface modification by low pressure plasma to improve its characteristics towards biomedical applications.
abstract: Poly(dimethyl siloxane) elastomer, (PDMS) is widely used as a biomaterial. However, PDMS is very hydrophobic and easily colonized by several bacteria and yeasts. Consequently, surface modification has been used to improve its wettability and reduce bacterial adhesion. The aim of this work was to modify the PDMS surface in order to improve its hydrophilicity and bacterial cell repulsion to be used as a biomaterial. Plasma was used to activate the PDMS surface and sequentially promote the attachment of a synthetic surfactant, Pluronic F-68, or a polymer, Poly(ethylene glycol) methyl methacrylate, PEGMA. Bare PDMS, PDMS argon plasma activated, PDMS coated with Pluronic F-68 and PEGMA-grafted PDMS were characterized by contact angle measurements, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The influence of the surface modifications on blood compatibility of the materials was evaluated by thrombosis and haemolysis assays. The cytotoxicity of these materials was tested for mouse macrophages. After modification, AFM results suggest the presence of a distinct layer at the surface and by the contact angle measures it was observed an increase of hydrophilicity. XPS analysis indicates an increase of the oxygen content at the surface as a result of the modification. All the studied materials revealed no toxicity and were found to be non-haemolytic or in some cases slightly haemolytic. Therefore, plasma was found to be an effective technique for the PDMS surface modification.
authors.affiliation: Department of Chemical Engineering, University of Coimbra, Polo II, Pinhal de Marrocos, Rua Sílvio Lima, 3030-790 Coimbra, Portugal. susanacspinto@gmail.com
authors.forename: S
authors.initials: S
authors.lastname: Pinto
authors.forename: P
authors.initials: P
authors.lastname: Alves
authors.forename: C M
authors.initials: CM
authors.lastname: Matos
authors.forename: A C
authors.initials: AC
authors.lastname: Santos
authors.forename: L R
authors.initials: LR
authors.lastname: Rodrigues
authors.forename: J A
authors.initials: JA
authors.lastname: Teixeira
authors.forename: M H
authors.initials: MH
authors.lastname: Gil
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000494:pharmacology; D020811:Biomedical Technology / Q000379:methods; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004129:Dimethylpolysiloxanes / Q000737:chemistry* / Q000494:pharmacology; D020724:Elastomers / Q000737:chemistry / Q000494:pharmacology; D006461:Hemolysis / Q000187:drug effects; D057927:Hydrophobic and Hydrophilic Interactions; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000187:drug effects; D008422:Materials Testing / Q000379:methods*; D008689:Methacrylates / Q000737:chemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D018625:Microscopy, Atomic Force; D056951:Photoelectron Spectroscopy; D020442:Poloxamer / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011817:Rabbits; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D004129:Dimethylpolysiloxanes; D020724:Elastomers; D008689:Methacrylates; C524499:polyethylene glycol methacrylate; D020442:Poloxamer; D011092:Polyethylene Glycols