Generation of zinc and copper incorporated oxide layers on titanium based biomaterials

Metal implants are designed to remain in the body as a prosthesis for solving bone damage problem. Bone tissue is damaged by the reason of osteoporosis, aging, accidents or similar reasons. The process of interaction between implant surface and bone tissue is obviously the key to the implant success. Surface morphology, composition, hydrophilicity and roughness are main factors of implant–bone tissue interaction and osseointegration. The aim of this study was to evaluate the bone-tissue response to a hydroxyapatite (HA) and calcium titanium oxide (CaTiO3) containing biocompatible compound layer modified commercially pure titanium (composed of rutile and anatase) samples and Ti6Al4V samples by micro-arc oxidation method (MAO). During the oxidation process, an electrolyte is including calcium and phosphorus ions and samples act as anode material, also stainless steel container as catode material. In this study, CpTi-MAO, CpTi-MAO-Zn and CpTi-MAO-Cu have been developed on Grade 4 quality commercially pure titanium (CpTi), 64-MAO and 64-MAO-Zn have been developed on titanium alloy (Ti6Al4V) with a single step micro-arc oxidation process. Properties of surface, i.e. surface thickness, morphology/pore size, crystal structure, chemical composition, roughness and hydrophilicity, were characterized with various analytical techniques. Introduction of zinc acetate and copper acetate into the electrolyte of the MAO process led to incorporation of 4-5 wt.% Zn or 7 wt.% Cu into the multi-layer coating on the CpTi-based samples were measured by EPMA. 4.82wt.% Zn, 2.43 wt.% Cu was specified by EDS. The Zn-doped Ti6Al4V-based samples have been showed 5.38 wt.% Zn by EDS. Osteoconductive calcium phosphate coatings enhanced the bioactivity, zinc and copper incorporated oxide layers showed non-cytotoxic properties during the releasing test into simulated body fluids. According to the XRD examination of the CpTi-MAO, the coatings are primarily composed of anatase and rutile TiO2 phases, α-titanium, hydroxylapatatite, CaTiO3. Additionally, effect of zinc and copper into the multi-layer coating during micro-arc oxidation process may expose excellent antibacterial efficiency without decreasing the bioactivity.