Bone implants procedures involve millions of people every year worldwide. One of the main factors determining implant success is related to the ability of the prostheses to osseointegrate, i.e. to create a structural and functional connection with the living bone.
Titanium and titanium alloys are widely used biomaterials for bone implants, due to their superior biocompatibility and corrosion resistance, suitable mechanical properties, and natural ability to osseointegrate. To further enhance the inherent tendency of this class of materials to bond with the host bone tissue, the surface of Ti-based implant is often modified to improve cell responses in terms of adhesion, proliferation and differentiation, all factors contributing to successful osseointegration. In particular, surface topography, both at the micro- and nanoscale, can enhance the implant-living bone interaction.
Herein, a possible surface modification strategy aimed at the creation of a dual-scale topography on two different titanium alloys, Ti-6Al-4V and Ti-5Al-5Mo-5V-3Cr, is presented. Dual-scale topography was obtained by electrochemically anodizing samples manufactured by selective laser melting to combine their intrinsic microtopography with the nanotopography offered by titanium dioxide nanotubes (TNTs) generated by anodization. Characterization of the as-printed and as-anodized samples was performed to evaluate parameters of significance in the context of osseointegration. Concerning wettability, it was observed that surfaces with TNTs exhibited high hydrophilicity. The influence of the anodization process parameters on TNTs morphology was examined, and linear dependence of the nanotube diameter on the voltage was identified. Annealing of the as-anodized samples showed that anatase was produced, while preserving the nanotube integrity. Preliminary studies to assess the bioactive properties of the samples showed the spreading of bone-like cells on these substrates and the deposition of mineral during simulated body fluid testing. Therefore, both studies provided promising results to corroborate the hypothesis that dual-scale topography could potentially improve osseointegration. / Thesis / Master of Applied Science (MASc) / Bone implants are often made of titanium-based materials, which, despite their suitable properties, may not sufficiently bond with the living bone tissue. This can lead to implant loosening and failure. To produce customized implants, additive manufacturing, or 3D-printing, can be employed. However, these surfaces require substantial post-processing to produce features capable of promoting bone integration. In this work, a dual-scale surface topography to combine the advantages of both micro- and nanoscale roughness was created using electrochemical anodization on 3D-printed titanium alloy substrates. Preliminary physical, chemical, and biological characterizations suggest that the creation of titania nanotubes on the 3D-printed surfaces of Ti-6Al-4V and Ti-5Al-5Mo-5V-3Cr could improve their ability to bond with bone.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/24104 |
| Date | January 2018 |
| Creators | Micheletti, Chiara |
| Contributors | Grandfield, Kathryn, Materials Science and Engineering |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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