title: Characterization of mechanical properties of hydroxyapatite-silicon-multi walled carbon nano tubes composite coatings synthesized by EPD on NiTi alloys for biomedical application.
abstract: Release of Ni(1+) ions from NiTi alloy into tissue environment, biological response on the surface of NiTi and the allergic reaction of atopic people towards Ni are challengeable issues for biomedical application. In this study, composite coatings of hydroxyapatite-silicon multi walled carbon nano-tubes with 20wt% Silicon and 1wt% multi walled carbon nano-tubes of HA were deposited on a NiTi substrate using electrophoretic methods. The SEM images of coated samples exhibit a continuous and compact morphology for hydroxyapatite-silicon and hydroxyapatite-silicon-multi walled carbon nano-tubes coatings. Nano-indentation analysis on different locations of coatings represents the highest elastic modulus (45.8GPa) for HA-Si-MWCNTs which is between the elastic modulus of NiTi substrate (66.5GPa) and bone tissue (≈30GPa). This results in decrease of stress gradient on coating-substrate-bone interfaces during performance. The results of nano-scratch analysis show the highest critical distance of delamination (2.5mm) and normal load before failure (837mN) as well as highest critical contact pressure for hydroxyapatite-silicon-multi walled carbon nano-tubes coating. The cell culture results show that human mesenchymal stem cells are able to adhere and proliferate on the pure hydroxyapatite and composite coatings. The presence of both silicon and multi walled carbon nano-tubes (CS3) in the hydroxyapatite coating induce more adherence of viable human mesenchymal stem cells in contrast to the HA coated samples with only silicon (CS2). These results make hydroxyapatite-silicon-multi walled carbon nano-tubes a promising composite coating for future bone implant application.
authors.affiliation: Department of Mechanical Engineering, University of Bonab, P.O. Box: 5551761167, Bonab, Iran. Electronic address: V_khalili@sut.ac.ir.
authors.forename: Vida
authors.initials: V
authors.lastname: Khalili
authors.affiliation: Research Center for Advanced Materials and Mineral Processing, Faculty of Materials Engineering, Sahand University of Technology, Tabriz, Iran; Biotechnology Research Center (BRC), Faculty of Chemical Engineering, Sahand University of Technology, Tabriz, Iran.
authors.forename: Jafar
authors.initials: J
authors.lastname: Khalil-Allafi
authors.affiliation: Bergmannsheil University Hospital/Surgical Research, Ruhr-University Bochum, Buerkle-de-la-Camp-Platz 1, 44789 Bochum, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Sengstock
authors.affiliation: Institute for Materials, Faculty of Mechanical Engineering, Ruhr-University Bochum, 44801 Bochum, Germany.
authors.forename: Yahya
authors.initials: Y
authors.lastname: Motemani
authors.affiliation: Institute for Materials, Faculty of Mechanical Engineering, Ruhr-University Bochum, 44801 Bochum, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Paulsen
authors.affiliation: Institute for Materials, Faculty of Mechanical Engineering, Ruhr-University Bochum, 44801 Bochum, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Frenzel
authors.affiliation: Institute for Materials, Faculty of Mechanical Engineering, Ruhr-University Bochum, 44801 Bochum, Germany.
authors.forename: Gunther
authors.initials: G
authors.lastname: Eggeler
authors.affiliation: Bergmannsheil University Hospital/Surgical Research, Ruhr-University Bochum, Buerkle-de-la-Camp-Platz 1, 44789 Bochum, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Köller
mesh_terms: D000497:Alloys; D002448:Cell Adhesion; D049109:Cell Proliferation; D002478:Cells, Cultured; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D059630:Mesenchymal Stem Cells / Q000166:cytology; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009532:Nickel; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties; D014025:Titanium
chemical_list: D000497:Alloys; D020099:Coated Materials, Biocompatible; D037742:Nanotubes, Carbon; D009532:Nickel; D017886:Durapatite; D014025:Titanium; D012825:Silicon
keywords: Composite coating; Electrophoretic deposition; Hydroxyapatite; Nano-indentation; Nano-scratch