Improvements in the corrosion resistance and biocompatibility of biomedical Ti–6Al–7Nb alloy using an electrochemical anodization treatment (original) (raw)
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Scientific Reports, 2018
Ti-24Nb-4Zr-8Sn (Ti2448), a new β-type Ti alloy, consists of nontoxic elements and exhibits a low uniaxial tensile elastic modulus of approximately 45 GPa for biomedical implant applications. Nevertheless, the bio-corrosion resistance and biocompatibility of Ti2448 alloys must be improved for long-term clinical use. In this study, a rapid electrochemical anodization treatment was used on Ti2448 alloys to enhance the bio-corrosion resistance and bone cell responses by altering the surface characteristics. The proposed anodization process produces a unique hybrid oxide layer (thickness 50–120 nm) comprising a mesoporous outer section and a dense inner section. Experiment results show that the dense inner section enhances the bio-corrosion resistance. Moreover, the mesoporous surface topography, which is on a similar scale as various biological species, improves the wettability, protein adsorption, focal adhesion complex formation and bone cell differentiation. Outside-in signals can b...
Materials Chemistry and Physics, 2019
Over the last decade, new titanium alloys are developed in different areas of implantology. The aim of this study was to characterize a new Ti-Al-Nb-Ta-Mo based alloy, with high potential for being used as a biomedical implant. The evaluation of Ti-6Al-2Nb-2Ta-1Mo was performed both in vitro (by monitoring its corrosion resistance in Hank's Balanced Salt Solution, HBSS) and in vivo (by evaluating the osseointegration following rabbit tibia implantation), by comparison with titanium and Ti-6Al-7Nb alloy. Electrochemical impedance spectroscopy (EIS) data showed high impedance values for all titanium samples after 1 week immersion times in HBSS at 37 o C. According to EIS analysis, the corrosion resistance of the Ti-6Al-2Nb-2Ta-1Mo alloy immersed in HBSS was higher compared to the standard cp-Ti or with the Ti-6Al-7Nb alloy. In addition, a higher degree of osseointegration was achieved by the Ti-6Al-2Nb-2Ta-1Mo alloy, thus probing that a higher resistance to electrochemical corrosion provided enhanced protection to the implant surface against biodegradation, thus positively affecting the qualitative and quantitative evolution of bone tissue repair.
Characterisation of bioactive films on Ti–6Al–4V alloy
Electrochimica Acta, 2013
In an attempt to increase the bioactivity and corrosion resistance of a Ti-6Al-4V alloy, the plasma electrolytic oxidation (PEO) process for surface modification was utilised. Selected samples were subjected to further treatment, either thermal or alkali. The morphology, chemical composition and phase composition of the ground and treated Ti-6Al-4V alloy substrates were investigated using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). It was observed that during the anodic process under sparking discharge conditions, the simultaneous incorporation of calcium and phosphorus in the forming oxide layer occurs. The resulting layers were porous and exhibited the typical morphology for layers formed during the PEO process. After the alkali treatment of samples oxidised at 140 V, a gel-like titanate layer was formed. The bioactivity investigations in simulated body fluid (SBF) solution and with human bone marrow stromal cells (MSCs) indicated that after anodising at 140 V and following alkali treatment the Ti-6Al-4V alloy exhibits osteoinductive properties. The electrochemical investigations showed that application of the anodising process of the Ti-6Al-4V alloy significantly improved its corrosion resistance in Ringer solution. The samples anodised at 80 V presented the highest corrosion resistance because of the formation of the thin, compact oxide layer on the alloy surface.
Corrosion Science, 2021
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Biochemical and Biophysical Research Communications, 2004
The biocompatibility of metal implants is related to their surface electrochemical characterizations. The in situ growing process of osteoblast-like U-2 OS cells on polished Ti and Ti-6Al-4V alloy during 72 h incubation was monitored using the electrochemical impedance spectroscopy (EIS) measurement technique. The results showed that the presence of cells on metals led to an increase in the impedance and polarization resistance (R p ) of metals. The impedance and R p increased as the cells grew (i.e., from adhesion, spreading to proliferation period). A trace amount of V element released from Ti-6Al-4V alloy led to a lower R p with respect to Ti metal during cell culture. In this study, a satisfactory equivalent circuit simulating the electrochemical characterizations of Ti and Ti-6Al-4V alloy cultured with cells was proposed. The EIS measurement technique was applied successfully to monitor the in situ growing process of U-2 OS cells on Ti and Ti-6Al-4V alloy.
Corrosion behavior and biocompatibility of nanostructured TiO2 film on Ti6Al4V
Journal of Biomedical Materials Research Part A, 2007
The corrosion behavior and cell adhesion property of nanostructured TiO2 films deposited electrolytically on Ti6Al4V were examined in the present in vitro study. The nanostructured TiO2 film deposition on Ti6Al4V was achieved via peroxoprecursors. SEM micrographs exhibit the formation of amorphous and crystallite TiO2 nanoparticles on Ti6Al4V before and after being annealed at 500°C. Corrosion behavior of TiO2-deposited and uncoated Ti6Al4V was evaluated in freely aerated Hank's solution at 37°C by the measurement and analysis of open-circuit potential variation with time, Tafel plots, and electrochemical impedance spectroscopy. The electrochemical results indicated that nano-TiO2 coated Ti6Al4V showed a better corrosion resistance in simulated biofluid than uncoated Ti6Al4V. Rat bone cells and human aortic smooth muscle cells were grown on these substrates to study the cellular responses in vitro. The SEM images revealed enhanced cell adhesion, cell spreading, and proliferation on nano-TiO2 coated Ti6Al4V compared to those grown on uncoated substrates for both cell lines. These results suggested that nanotopography produced by deposition of nanostructured TiO2 onto Ti alloy surfaces might enhance corrosion resistance, biocompatibility, and cell integration for implants made of Ti alloys. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
2022
This study aims to investigate the microstructure and electrochemical behavior of the laser powder bed fusion (LPBF-) and electron beam melting (EBM-) manufactured Ti-6Al-4 V alloy in the Ringer ′ s solution. The microstructure of the LPBF-fabricated part contained the acicular α' martensite phase, while the EBM-fabricated part possessed a combination of α and β phases. The formation of two phases in the EBM sample can be related to the lower thermal tension and higher temperature of the table during the fabrication process. Electrochemical studies have revealed that the better corrosion performance of the LPBF-manufactured alloy was mainly due to the formation of local galvanic cells in the EBM-manufactured Ti-6Al-4 V alloy. Corrosion current densities of the LPBF-and EBM-manufactured alloys after 100 h of immersion were 0.36 and 0.87 µA cm − 2 , respectively. MTT assay was performed using MG-63 cells to assess the biocompatibility of the manufactured samples. The results showed that the cells had good adhesion and durability on the samples. Though, both samples could be regarded as good candidates for implant applications, but the LPBF-manufactured part showed a higher resistance corrosion and is then more suitable for implant alloys.
Journal of Materials Science-materials in Medicine, 2011
Titanium and its alloys represent the gold standard for orthopaedic and dental prosthetic devices, because of their good mechanical properties and biocompatibility. Recent research has been focused on surface treatments designed to promote their rapid osteointegration also in case of poor bone quality. A new surface treatment has been investigated in this research work, in order to improve tissue integration of titanium based implants. The surface treatment is able to induce a bioactive behaviour, without the introduction of a coating, and preserving mechanical properties of Ti6Al4V substrates (fatigue resistance). The application of the proposed technique results in a complex surface topography, characterized by the combination of a micro-roughness and a nanotexture, which can be coupled with the conventional macro-roughness induced by blasting. Modified metallic surfaces are rich in hydroxyls groups: this feature is extremely important for inorganic bioactivity (in vitro and in vivo apatite precipitation) and also for further functionalization procedures (grafting of biomolecules). Modified Ti6Al4V induced hydroxyapatite precipitation after 15 days soaking in simulated body fluid (SBF). The process was optimised in order to not induce cracks or damages on the surface. The surface oxide layer presents high scratch resistance.
Journal of Functional Biomaterials
Additive technologies allowed for the development of medicine and implantology, enabling the production of personalized and highly porous implants. Although implants of this type are used clinically, they are usually only heat treated. Surface modification using electrochemical methods can significantly improve the biocompatibility of biomaterials used for implants, including printed ones. The study examined the effect of anodizing oxidation on the biocompatibility of a porous implant made of Ti6Al4V by the SLM method. The study used a proprietary spinal implant intended for the treatment of discopathy in the c4–c5 section. As part of the work, the manufactured implant was assessed in terms of compliance with the requirements for implants (structure testing—metallography) and the accuracy of the pores produced (pore size and porosity). The samples were subjected to surface modification using anodic oxidation. The research was carried out for 6 weeks in in vitro conditions. Surface t...