Biocompatibility and mechanical properties of diamond‐like coatings on cobalt‐chromium‐molybdenum steel and titanium‐aluminum‐vanadium biomedical alloys

Media type: E-Article
Title: Biocompatibility and mechanical properties of diamond‐like coatings on cobalt‐chromium‐molybdenum steel and titanium‐aluminum‐vanadium biomedical alloys
Contributor: Hinüber, C.; Kleemann, C.; Friederichs, R. J.; Haubold, L.; Scheibe, H. J.; Schuelke, T.; Boehlert, C.; Baumann, M. J.
imprint: Wiley, 2010
Published in: Journal of Biomedical Materials Research Part A
Language: English
DOI: 10.1002/jbm.a.32851
ISSN: 1549-3296; 1552-4965
Keywords: Metals and Alloys ; Biomedical Engineering ; Biomaterials ; Ceramics and Composites
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Description: <jats:title>Abstract</jats:title><jats:p>Diamond‐like carbon (DLC) films are favored for wear components because of diamond‐like hardness, low friction, low wear, and high corrosion resistance (Schultz et al., Mat‐wiss u Werkstofftech 2004;35:924–928; Lappalainen et al., J Biomed Mater Res B Appl Biomater 2003;66B:410–413; Tiainen, Diam Relat Mater 2001;10:153–160). Several studies have demonstrated their inertness, nontoxicity, and the biocompatibility, which has led to interest among manufacturers of surgical implants (Allen et al., J Biomed Mater Res B Appl Biomater 2001;58:319–328; Uzumaki et al., Diam Relat Mater 2006;15:982–988; Hauert, Diam Relat Mater 2003;12:583–589; Grill, Diam Relat Mater 2003;12:166–170). In this study, hydrogen‐free amorphous, tetrahedrally bonded DLC films (ta‐C) were deposited at low temperatures by physical vapor deposition on medical grade Co28Cr6Mo steel and the titanium alloy Ti6Al4V (Scheibe et al., Surf Coat Tech 1996;85:209–214). The mechanical performance of the ta‐C was characterized by measuring its surface roughness, contact angle, adhesion, and wear behavior, whereas the biocompatibility was assessed by osteoblast (OB) attachment and cell viability via Live/Dead assay. There was no statistical difference found in the wettability as measured by contact angle measurements for the ta‐C coated and the uncoated samples of either Co28Cr6Mo or Ti6Al4V. Rockwell C indentation and dynamic scratch testing on 2–10 μm thick ta‐C films on Co28Cr6Mo substrates showed excellent adhesion with HF1 grade and up to 48 <jats:italic>N</jats:italic> for the critical load <jats:italic>L</jats:italic><jats:sub>C2</jats:sub> during scratch testing. The ta‐C coating reduced the wear from 3.5 × 10<jats:sup>−5</jats:sup> mm<jats:sup>3</jats:sup>/Nm for an uncoated control sample (uncoated Co28Cr6Mo against uncoated stainless steel) to 1.1 × 10<jats:sup>−7</jats:sup> mm<jats:sup>3</jats:sup>/Nm (coated Co28Cr6Mo against uncoated stainless steel) in reciprocating pin‐on‐disk testing. The lowest wear factor of 3.9 × 10<jats:sup>−10</jats:sup> mm<jats:sup>3</jats:sup>/Nm was measured using a ta‐C coated steel ball running against a ta‐C coated and polished Co28Cr6Mo disk. Student's <jats:italic>t</jats:italic>‐test found that the ta‐C coating had no statistically significant (<jats:italic>p</jats:italic> < 0.05) effect on OB attachment, when compared with the uncoated control samples. There was no significant difference (<jats:italic>p</jats:italic> < 0.05) in the Live/Dead assay results in cell death between the ta‐C coated Co28Cr6Mo and Ti6Al4V samples and the uncoated controls. Therefore, these ta‐C coatings show improved wear and corrosion (Dorner‐Reisel et al., Diam Relat Mater 2003;11:823–827; Affato et al., J Biomed Mater Res B Appl Biomater 2000;53:221–226; Dorner‐Reisel et al., Surf Coat Tech 2004;177–178:830–837; Kim et al., Diam Relat Mater 2004;14:35–41) performance and excellent <jats:italic>in vitro</jats:italic> cyto‐compatibility, when compared with currently used uncoated Co28Cr6Mo and Ti6Al4V implant materials. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.</jats:p>

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