The biocompatibility of nanotubular oxide layer formed on the ultrafine-grained Ti-13Nb-13Zr alloy

Abstract

Primary stability of biomaterials is associated with the mechanical contact of an implant with the surrounding bone, which is governed by surface properties. The implant often needs some kind of modification to optimize and improve biological properties of the surface. In the present study, nanotubular oxide layer on Ti-13Nb-13Zr alloy (coarse-grained, CG, and ultrafine-grained, UFG, obtained by high pressure torsion) alloy was formed by means of electrochemical anodization in the 1M H3PO4 + NaF electrolyte, during 60 and 90 minutes. The atomic force microscopy (AFM) was studied to characterize the surface topography and it was shown that highly ordered nanotubular layers were obtained by anodization. Also, results show that increasing anodizing time increases roughness of the surface. The aim of this paper is to determine the vitro biocompatibility of the titanium alloy after electrochemical anodization. In vitro nanotubular oxide layer examinations were performed on the human fibroblast cell lines (MRC-5). The cytotoxicity of the examined materials was measured as a percent of cell growth inhibition using in vitro colorimetric methyl-thiazol-tetrazolium (MTT) test. Scanning Electron Microscope (SEM) observation of MRC-5 cell was performed using a SEM MIRA3 TESCAN which operated at an accelerating voltage of 4.5 keV. Results show that nanotubular oxide layer formed on the UFG Ti-13Nb-13Zr alloy during 90 minutes indicates better cells contact and spreading along nanotubular surface.