title: Cytocompatibility of nitrogen plasma ion immersed medical cobalt-chromium alloys.
abstract: Wear particles and ion release from medical CoCr contribute to the risk for aseptic loosening. Nitrogen plasma immersion ion implantation (PIII) has been shown to reduce wear of CoCr but is associated with increased Co ion release. This work investigated the cytocompatibility of CoCr modified by nitrogen PIII at different temperatures (mCoCr). The osteosarcoma cell line Saos-2, mesenchymal stem cells (MSCs), and mononuclear cells (MNCs) were grown directly on CoCr/mCoCr discs or treated with CoCl2. Proliferation and metabolic activity of Saos-2 and MSC were decreased on mCoCr in correlation with increasing implantation temperature. The elevated Co ion release seemed to play a decisive role since analog effects were observed by treatment of cells with CoCl2. Proliferation of phytohemagglutinin-stimulated MNC was reduced in the presence of CoCr discs or CoCl2. For MNC-alloy cultures we observed an increase in interleukin 2 (IL-2) and a decrease in interferon γ (IFN-γ) and IL-10 secretion compared to cultures without alloys. The results of this study demonstrate that PIII process temperature and corresponding Co ion release correlate with material cytocompatibility. Therefore, the two competing parameters, reduction of wear and increase in Co ions, have to be taken into consideration for the evaluation of the clinical applicability of nitrogen-implanted CoCr.
authors.affiliation: Translational Centre for Regenerative Medicine (TRM), Universität Leipzig, 04103, Leipzig, Germany; Pharmaceutical Technology, Institute of Pharmacy, Universität Leipzig, 04317, Leipzig, Germany.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Schröck
authors.forename: Heike
authors.initials: H
authors.lastname: Schneider
authors.forename: Johanna
authors.initials: J
authors.lastname: Lutz
authors.forename: Michael C
authors.initials: MC
authors.lastname: Hacker
authors.forename: Stephan
authors.initials: S
authors.lastname: Mändl
authors.forename: Manja
authors.initials: M
authors.lastname: Kamprad
authors.forename: Michaela
authors.initials: M
authors.lastname: Schulz-Siegmund
mesh_terms: D000328:Adult; D001672:Biocompatible Materials / Q000737:chemistry / Q000633:toxicity*; D002460:Cell Line; D002470:Cell Survival; D002858:Chromium Alloys / Q000737:chemistry / Q000633:toxicity*; D003035:Cobalt / Q000737:chemistry / Q000633:toxicity*; D016207:Cytokines / Q000032:analysis; D004249:DNA Damage; D006801:Humans; D008422:Materials Testing; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism; D009584:Nitrogen / Q000737:chemistry / Q000633:toxicity*; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D013499:Surface Properties; D055815:Young Adult
chemical_list: D001672:Biocompatible Materials; D002858:Chromium Alloys; D016207:Cytokines; D003035:Cobalt; D009584:Nitrogen
keywords: MSC; Saos-2; cobalt-chromium alloy; cytocompatibility; cytokines; mononuclear cells