Title: A review of surface modification of a novel low modulus β-type titanium alloy for biomedical applications

Authors: Mitsuo Niinomi; Masaaki Nakai; Junko Hieda; Ken Cho; Toshihiro Kasuga; Tomokazu Hattori; Takashi Goto; Takao Hanawa

Addresses: Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan ' Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan ' Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan ' Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan ' Department of Environmental and Materials Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan ' Department of Materials Science and Engineering, Faculty of Science and Technology, Meijo University, Nagoya 468-8502, Japan ' Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan ' Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo 101-0062, Japan

Abstract: Ti-29Nb-13Ta-4.6Zr (TNTZ) is a novel β-type titanium alloy that has great potential use in biomedical implants because of its relatively low Young's modulus (around 60 GPa), which minimise bone atrophy due to stress shielding. However, the biocompatibility and bio-functionality of TNTZ is poor. Therefore, a bioactive ceramic surface modification or soft-tissue-compatible polymer surface modification is advantageous for enhancing the biological properties of TNTZ. The bio-functionality of TNTZ itself, and that modified with a coating hydroxyapatite (HAp) using alkali treatment, electrochemical treatment, and dip-coating treatment with calcium phosphate glass ceramic or metal organic chemical vapour deposition (MOCVD) is assessed. In addition, modification of TNTZ with soft-tissue-compatible segmented polyurethane (SPU) using different silane coupling agents is described. The bonding strength of the bioactive ceramic and soft-tissue compatible polymer with the TNTZ is assessed with respect to variations in surface roughness.

Keywords: Ti-29Nb-13Ta-4.6Zr; TNTZ; surface modification; hydroxyapatite; HAp; segmented polyurethane; SPU; osteoconductivity; surface roughness; surface quality; titanium alloys; biomedical implants; biocompatibility; biofunctionality; bonding strength; bioactive ceramics; soft tissue compatible polymers; soft tissue compatibility.

DOI: 10.1504/IJSURFSE.2014.060487

International Journal of Surface Science and Engineering, 2014 Vol.8 No.2/3, pp.138 - 152

Received: 01 Feb 2013
Accepted: 06 Jul 2013

Published online: 17 Apr 2014 *

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