title: Influences of dehydration and rehydration on the lubrication properties of phospholipid polymer-grafted cross-linked polyethylene.
abstract: Surface modification by grafting of biocompatible phospholipid polymer onto the surface of artificial joint material has been proposed to reduce the risk of aseptic loosening and improve the durability. Poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC)-grafted cross-linked polyethylene (CLPE) has shown promising results for reducing wear of CLPE. The main lubrication mechanism for the PMPC layer is considered to be the hydration lubrication. In this study, the lubrication properties of PMPC-grafted CLPE were evaluated in reciprocating friction test with rehydration process by unloading in various lubricants. The start-up friction of PMPC-grafted CLPE was reduced, and the damage of PMPC layer was suppressed by rehydration in water or hyaluronic acid solutions. In contrast, the start-up friction of PMPC-grafted CLPE increased in fetal bovine serum solution, and the damage for PMPC layer was quite noticeable. Interestingly, the start-up friction of PMPC-grafted CLPE was reduced in fetal bovine serum solution containing hyaluronic acid, and the damage of the PMPC layer was suppressed. These results indicate that the rehydration by unloading and hyaluronic acid are elemental in maximizing the lubrication effect of hydrated PMPC layer.
authors.affiliation: Research Center for Advanced Biomechanics, Kyushu University, Fukuoka, Japan Faculty of System Design, Tokyo Metropolitan University, Tokyo, Japan yarimitsu@tmu.ac.jp.
authors.forename: Seido
authors.initials: S
authors.lastname: Yarimitsu
authors.affiliation: Division of Science for Joint Reconstruction, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan Sensory & Motor System Medicine, Faculty of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Moro
authors.affiliation: Division of Science for Joint Reconstruction, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan Department of Materials Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan Research Department, KYOCERA Medical Corporation, Osaka, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kyomoto
authors.affiliation: Division of Science for Joint Reconstruction, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan Research Department, KYOCERA Medical Corporation, Osaka, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Sensory & Motor System Medicine, Faculty of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Sakae
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Department of Materials Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ishihara
authors.affiliation: Research Center for Advanced Biomechanics, Kyushu University, Fukuoka, Japan.
authors.forename: Teruo
authors.initials: T
authors.lastname: Murakami
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D017276:Friction; D007595:Joint Prosthesis; D054327:Lubricants / Q000737:chemistry*; D008422:Materials Testing; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000737:chemistry; D020959:Polyethylene / Q000737:chemistry*; D011109:Polymethacrylic Acids / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D054327:Lubricants; D011109:Polymethacrylic Acids; C115766:poly(2-methacryloyloxyethyl-phosphorylcholine); D014867:Water; D010767:Phosphorylcholine; D020959:Polyethylene
keywords: Artificial joint; MPC polymer; friction; hydration lubrication; wear