Enhanced wear resistance of modified cross-linked polyethylene by grafting with poly(2-methacryloyloxyethyl phosphorylcholine)

Masayuki Kyomoto, Toru Moro, Tomohiro Konno, Hiroaki Takadama, Noboru Yamawaki, Hiroshi Kawaguchi, Yoshio Takatori, Kozo Nakamura, Kazuhiko Ishihara

Research output: Contribution to journalArticlepeer-review

56 Citations (Scopus)

Abstract

We developed a cross-linked polyethylene (CLPE) modified with a phospholipid polymer in order to address the serious problem of osteolysis caused by wear particles derived from the polyethylene components of artificial hip joints. Our goal of preventing aseptic loosening could be achieved by avoiding any formation of CLPE wear particles or suppressing the activation of cell systems by the wear particles. We investigated the surface and wear resistance properties of 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer grafted onto the surface of CLPE (CLPE-g-MPC). The relative density of MPC polymer chains was determined by the P-O group index. Generally, polymerization times correspond to the number of polymer chains in radical polymerization. After 3.0 × 106 cycles in a hip joint simulator test, the steady wear rates of the untreated CLPE and CLPE-g-MPC cups with a low P-O group index were as high as 4 mg/106 cycles; those of the CLPE-g-MPC cups with high P-O group indexes, that is, 0.46 and 0.48, markedly decreased to -1.12 and 0.16 mg/106 cycles, respectively. Therefore, the grafting of an MPC polymer with high density would be essential in order to maintain the long-term wear resistance of CLPE-g-MPC as an orthopedic bearing material.

Original languageEnglish
Pages (from-to)10-17
Number of pages8
JournalJournal of Biomedical Materials Research - Part A
Volume82
Issue number1
DOIs
Publication statusPublished - 2007 Jul 1
Externally publishedYes

Keywords

  • Joint replacements
  • Phospholipid
  • Phosphorylcholine
  • Polyethylene
  • Wear mechanisms

ASJC Scopus subject areas

  • Ceramics and Composites
  • Biomaterials
  • Biomedical Engineering
  • Metals and Alloys

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