On the relation between surface texture of metallic implants and their bioactivity

The aim of this study is to emphasize a neglected aspect of the surface properties of metallic implants. The authors have investigated the effects of the different forming processes on the atomic arrangement and subsequent biological activity of the surface of titanium (Ti)-based materials. First, the authors have shown how the fabrication method can influence titanium implants’ surface grain orientations. Implants were exposed to simulated body fluid (SBF) and cell culture experiments to analyze their biological activity afterward. Pole figure and orientation distribution function measurements indicate that the main crystallographic orientation is (10-10) in the extruded sample, while (0002) is determined as the predominant crystallographic plane in the rolled sample. Grazing-angle X-ray diffraction and scanning electron microscopy analyses of the substrates after immersion in SBF show that the number and sizes, as well as morphology, of calcium phosphate crystals formed on the surface of the samples are clearly dissimilar. The biological assessments of the implants with human bone marrow mesenchymal stem cells have shown that the Ti-(10-10) orientation is the favored orientation for hard tissue regeneration. This research shows how the crystallographic orientation of metallic materials can be used to improve the biological activity of biomaterials in contact with bone tissue.