Biofunctional Surface Layer and its Bonding Strength in Low Modulus β-Type Titanium Alloy for Biomedical Applications

Abstract

Recently, low-modulus β-type titanium alloys have been the focus of considerable attention because of their high biocompatibility and their low moduli that make them effective for inhibiting bone atrophy and for enhancing bone remodeling. However, the biofunctinalities of titanium alloys, such as bone conductivity, blood compatibility, and soft tissue compatibility, are poor. Therefore, surface modification techniques such as bioactive ceramic surface modification and blood-and soft-tissue-compatible polymer surface modification are applied to titanium alloys. Hydroxyapatite (HAp) surface modification via metal organic chemical vapor deposition (MOCVD) and segmented polyurethane (SPU) surface modification via silane coupling treatment are effective techniques to add biofunctionalites to titanium alloys. HAp surface modification via MOCVD and SPU surface modification using three kinds of silane coupling agents on a low modulus beta-type titanium alloy, namely, TNTZ, are discussed. Moreover, the bonding strengths of HAp and SPU on the surface of TNTZ, which are important parameters, are also discussed.