Special Issue "Titanium Materials for Biomedical Application"

Guest Editor
Prof. Dr. Barbara D. Boyan
Wallace H. Coulter Dept. of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0363, USA
Website: http://www.bme.gatech.edu/facultystaff/faculty_record.php?id=48
E-Mail:
Phone: +1 404 385 4108
Fax: +1 404 894 2291

Submission

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed Open Access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 800 CHF (Swiss Francs).

Type of paper: Article
Title: Ab Initio Study of Elastic Properties of Dual-Phase Ti-Nb Alloys
Authors: Martin Friak et al.
Affiliation: Max-Planck-Institut fuer Eisenforschung GmbH, Max-Planck-Strasse 1, D-402 37, Duesseldorf, Germany; Tel.: +49-211-6792-461; Fax: +49-211-6792-465; E-Mail: m.friak@mpie.de
Abstract: We present a scale-bridging approach for modelling the integral elastic response of two-phase polycrystalline Ti-Nb composite that is based on a combination of (i) quantum-mechanical calculations of thermodynamic phase stability and single-crystal elastic stiffness, and (ii) homogenization schemes intended for multi-phase polycrystalline aggregates. The modeling is used as a theory-guided bottom-up materials design strategy and applied to Ti-Nb alloys as a promising candidate for biomedical implant applications. The theoretical results (i) show an excellent agreement with experimental data and (ii) reveal a decisive influence of the multi-phase character of the polycrystalline composites on their integral elastic properties. The study shows that the results based on the density-functional-theory calculations at the atomistic level can be directly used for predictions at the macroscopic scale, effectively scale-jumping several orders of magnitude without using any empirical parameters.

Title: Effect of alkyl chain length on carboxylic acid SAMs on Ti-6Al-4V
Authors: Gavin A. Buckholtz and Ellen S. Gawalt *
Affiliation: The formation of methyl-terminated carboxylic acid self-assembled monolayers (SAMs) with even numbers of carbons, from eighteen to thirty, was investigated on the oxide surface of Ti-6Al-4V and component metal oxides.  Modified surfaces were characterized using diffuse reflectance infrared Fourier transform spectroscopy, matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and contact angle analysis.  Infrared spectroscopy indicated that using aerosol spray deposition methods, stable, all-trans SAMs of octacosanoic (28 carbons) and triacontanoic (30 carbons) acid, were formed on the alloy.  Films formed on titanium and aluminum oxide are similar to the alloy, whereas vanadium oxide showed limited reactivity.  MALDI-TOF MS confirmed that formed films were monolayers, with no multilayers or aggregates present.  Water contact angles were indicative of the presence of the hydrophobic methyl groups at the interface.

Title: Automatic Actin Filament Quantification of Osteoblasts and Their Morphometric Analysis on Microtextured Silicon-Titanium Arrays
Authors: Claudia Matschegewski ¹, Susanne Staehlke ¹, Harald Birkholz ², Regina Lange ³, Ulrich Beck ³, Konrad Engel ² and J. Barbara Nebe ^1,*
Affiliations: ¹ Biomedical Research Center, Department of Cell Biology, University of Rostock, Schillingallee 69, D-18057 Rostock, Germany; E-Mail: barbara.nebe@med.uni-rostock.de; Tel.: +49 381 494 7771; Fax: +49 381 494 7764
² Institute of Mathematics, University of Rostock, Ulmenstrasse 69, D-18057 Rostock, Germany
³ Department of Electrical Engineering and Informatics, University of Rostock, A.-Einstein-Str. 2, D-18059 Rostock, Germany
Abstract: Microtexturing of implant surfaces is of major relevance in the endeavor to improve biorelevant implant designs. In order to elucidate the role of a biomaterial’s topography on cell physiology, obtaining quantitative correlations between cellular behavior and distinct microarchitectural properties is in great demand. Until now, the microscopically observed reorganization of the cytoskeleton on structured biomaterials has been difficult to convert into data. We used geometrically microtextured silicon-titanium arrays as a model system. Samples were prepared by deep reactive-ion etching of silicon wafers, resulting in rectangular grooves (width and height: 2 µm) and cubic pillar structures (pillar dimensions: 2 × 2 × 5 and 5 × 5 × 5 µm); finally sputter-coated with 100 nm titanium. We focused on the morphometric analysis of MG-63 osteoblasts, including a quantification of the actin cytoskeleton. By means of our novel software FilaQuant, especially developed for automatic actin filament recognition, we were first able to quantify the alterations of the actin filament network dependent on the microtexture of a material surface. The cells’ actin fibers were significantly reduced in length on the pillared surfaces versus the grooved array (4–5 fold) and completely reorganized on the micropillars, but without altering the orientation of cells. Our morpho-functional approach opens new possibilities for the data correlation of cell-material interactions.
Keywords: actin cytoskeleton; MG-63 osteoblasts; microtexturing; ridge detection; image processing