Ti Nanotubes Research Articles

Electro-, photo-, and photoelectrochemical degradation of chloramphenicol on self-doping Ti nanotubes.

In this work, the photo-, electro-, and photo-electro-oxidation of chloramphenicol was investigated. The photo-experiments were carried out with different irradiation sources (an ultraviolet and a simulated solar source) using self-doped titanium nanotubes (SDTNT), a very promising and innovative material that deserves further investigations in the degradation of different pollutants. The photo-electrooxidation (j = 15mAcm-2) under simulated solar irradiation presented the best efficiency, with ca. 100% degradation and kinetic constant of k = 0.04427min-1. The FTIR analysis demonstrated a structural modification of the standard molecule occurred for all conditions used, suggesting a modification in functional groups responsible for the biological activity. Furthermore, the TOC analysis showed a significant mineralization of the pollutant (66% from the initial concentration). In addition, both photo-electrooxidation approaches have demonstrated a positive value of S, where the simulated solar irradiation reached the highest value S = 0.6960. The experimental results pointed out evidence that the methodology employed herein for chloramphenicol degradation is greatly interesting and the photo-electrooxidation under simulated solar irradiation is a promising approach for this purpose.

Electrophoretic deposition of gentamicin and chitosan into titanium nanotubes to target periprosthetic joint infection.

Periprosthetic joint infection (PJI) occurs in 1%-2% of primary total hip and knee arthroplasties; the rate can reach 20% in individuals at risk. Due to the low local bioavailability of systemic antibiotics and possible off-target effects, localized drug delivery systems are of great importance. Our aim was the electrophoretic deposition (EPD) of gentamicin and chitosan in Titanium (Ti) nanotubes to establish a local, prolonged antibiotic delivery. Nanotubes were created on Ti wire with a two-step anodization process. For drug deposition, EPD and the air-dry methods were compared. For a prolonged drug release, gentamicin and crosslinked chitosan were deposited in a two-step EPD process. Drug release was quantified by fractional volume sampling. The Ti wires were tested against Staphylococcus aureus by agar dilution and liquid culture methods. MC3T3-E1 osteoblastic cell viability was determined with trypan blue. Nanotubes were characterized by a 100 nm diameter and 7 μm length. EPD allowed a higher amount of gentamicin deposited than the air-dry method. Drug deposition was controllable by adjusting the voltage and duration of the EPD process. The crosslinked chitosan layer allowed diffusion-driven release kinetics for up to 3 days. Gentamicin-loaded Ti wires significantly inhibited bacterial growth and resulted in a larger inhibition zone compared to unloaded wires. Twenty-four hours of incubation with loaded wires did not have a significant effect on osteoblast viability. Gentamicin-loaded Ti nanotubes represent a promising approach for PJI prevention, as well as a valuable preclinical tool for the investigation of localized drug delivery systems created on Ti surface.

Photoelectrocatalysis performance of Se doped-TiO2/Ti nanotube arrays for visible-light-driven degradation of diazinon pesticide

Photoelectrocatalysis performance of Se doped-TiO2/Ti nanotube arrays for visible-light-driven degradation of diazinon pesticide

Promoting osseointegration of titanium by pH-responsive releasing of H2S and optimizing polarization time for macrophages

To improve the osteointegration of titanium implant by macrophages immunoregulation, in this study, a functionalized titanium implant was fabricated by storing H2S donors (JK-1) into Ti nanotubes and plugging with chitosan/gelatin multilayers. After implantation, the inflammation responses were initiated immediately and overlaps with the subsequent regeneration phase. The acidic inflammatory environment could trigger the degradation of multilayers and release of H2S. By optimizing polarization regulation time of M1 to M2 macrophages, we can maintain the phagocytosis and neovascularization functions of M1 macrophages and improve anti-inflammatory response timely by M2 macrophages polarization. And in turn the immunomodulation of macrophage could lead to the efficient osteogenic differentiation of MSCs. In vivo results showed that keeping M1 macrophages for 2 or 3 days could promote neovascularization around implants. Subsequent M2 macrophages polarization could improve osteogenesis. So, it is a promising strategy for titanium implants improvement was supplied that a better osseointegration of titanium-based implants could be possessed by macrophages immunomodulation.

Electrochemical reduction of CO2 on Cu doped titanium nanotubes—An insight on ethylene selectivity

Electrochemical reduction of CO2 is performed on Cu electrodeposited Ti nanotubes (Cu/TiNT). TiNT is prepared by anodization method followed by electrodeposition of Cu and the CO2 reduction achieved is compared with that of bare electrodes. The comparison between Cu/TiNT and TiNT is done based on the characterization techniques of Scanning Electron Microscopy, X-ray Diffraction, Transmission Electron Microscopy, X-ray Photoelectron Spectroscopy and UV-Diffuse Reflectance Spectroscopy. Electrochemical reduction of CO2 is carried out in an H-type cell with 0.5 M KCl electrolyte, and ethylene, methane, formic acid, CO, hydrogen along with methanol and ethanol are observed as trace products. Among the electrodes studied, maximum Faradaic efficiency (55%) is observed for Cu/TiNT compared to TiNT and bare electrodes. To understand the mechanism of CO2 reduction which produces ethylene on the surface, calculations of first principles are carried out for the Ti nanotubes with Cu deposition on the surface and the binding configurations of various intermediates are studied. The result of first principle calculation shows that the ethylene formation on the Cu deposited surface is favorable than the methane which is in line with the experimental observation.

Enhanced quinoline degradation by 3D stack Z-scheme photoelectrocatalytic system with Ag-TNTs photoanode and CN-CNWs photocathode

A novel 3D Stack Z-scheme photoelectrocatalytic (PEC) system was set up with Ag-TiO2/Ti nanotubes (Ag-TNTs) photoanode and g-C3N4/Cu2O/Cu nanowires (CN-CNWs) photocathode to realize efficient quinoline removal. Multiple mesh photoelectrodes were arranged in an alternating form (anode-cathode-anode) in the reactor to make full use of light and increase the contact possibility between catalysts and contaminants. Results suggested that the PEC system, CN-CNWs photocathode and O2 condition could enhance the quinoline removal. Radical quenching experiment confirmed that hydroxyl radical (·OH) was dominant reactive oxygen species (ROS) in the PEC system and superoxide radical (·O2-) generated on cathode was the reason for the increased quinoline removal efficiency with O2. Compared with Cu2O/Cu, the CN-CNWs photocathode generated more H2O2 under different conditions. The mechanism was proposed: Driven by the bias, the anode electrons and cathode holes recombined and realized the simultaneous oxidation and reduction as a Z-scheme. It enhanced the reactions on both photoelectrodes and improved the system efficiency. This study provided a new and promising insight into the development of a novel PEC system for environmental remediation.

Nanostructured Surfaces to Promote Osteoblast Proliferation and Minimize Bacterial Adhesion on Titanium.

The objective of this study was to investigate the potential of titanium nanotubes to promote the proliferation of human osteoblasts and to reduce monomicrobial biofilm adhesion. A secondary objective was to determine the effect of silicon carbide (SiC) on these nanostructured surfaces. Anodized titanium sheets with 100–150 nm nanotubes were either coated or not coated with SiC. After 24 h of osteoblast cultivation on the samples, cells were observed on all titanium sheets by SEM. In addition, the cytotoxicity was evaluated by CellTiter-BlueCell assay after 1, 3, and 7 days. The samples were also cultivated in culture medium with microorganisms incubated anaerobically with respective predominant periodontal bacteria viz. Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia as monoinfection at 37 °C for 30 days. The biofilm adhesion and coverage were evaluated through surface observation using Scanning Electron Microscopy (SEM). The results demonstrate that Ti nanostructured surfaces induced more cell proliferation after seven days. All groups presented no cytotoxic effects on human osteoblasts. In addition, SEM images illustrate that Ti nanostructured surfaces exhibited lower biofilm coverage compared to the reference samples. These results indicate that Ti nanotubes promoted osteoblasts proliferation and induced cell proliferation on the surface, compared with the controls. Ti nanotubes also reduced biofilm adhesion on titanium implant surfaces.

Mussel adhesive protein blended with gelatin loaded into nanotube titanium dental implants enhances osseointegration.

The purpose of this study was to investigate whether mussel adhesive protein (MAP) blended with gelatin loaded into nanotube titanium (Ti) dental implants enhances osseointegration and supports bone formation. Cell viability, crystal violet staining, Western blot analysis, alizarin red S staining, alkaline phosphatase (ALP) activity, micro-computed tomography (μ-CT), hematoxylin and eosin (H&E), and immunohistochemistry (IHC) staining were employed to test the biocompatibility of MAP blended with gelatin (MAP/Gel). MC3T3 E1 cells were used for in vitro and Sprague-Dawley rats for in vivo models in this study. MC3T3 E1 cells cultured in MAP/Gel loaded into nanotube Ti surface demonstrated activation of FAK-PI3K-MAPKs-Wnt/β-catenin signaling pathway and enhanced osteogenic differentiation. μ-CT, H&E, and IHC staining confirmed that MAP/Gel dental implants promoted bone regeneration around the nanotube Ti implants by upregulation of Runx-2, BMP-2/7, Osterix, and OPG in rat mandible model. MAP/Gel supports osseointegration of dental implant after implantation. It is hypothesized that MAP/Gel loaded into nanotube Ti dental implants may be applicable as a potential treatment for bone formation and proper integration of dental implants with alveolar bone. Graphical abstract.

Highly efficient and mild electrochemical degradation of bentazon by nano-diamond doped PbO2 anode with reduced Ti nanotube as the interlayer

Anodic oxidation based on PbO2 anode has been demonstrated as the feasible approach for the decontamination of organic pollutants; however, the performance of this process is hindered by its ordinary electrochemical activity and relatively low stability. In this study, we fabricated an efficient Ti/TiO2-RNTs/Sb-SnO2/PbO2-ND electrode with electrochemically reduced TiO2 nanotubes as the interlayer and nano-diamond as the dopant. As compared with other electrodes, the constructed Ti/TiO2-RNTs/Sb-SnO2/PbO2-ND exhibited higher oxygen evolution overpotential, larger active area and less charge transfer resistance. Thus, the average current efficiency of 30% could be attained at 120 min with TiO2-NTs/Sb-SnO2/PbO2, which was 1.5 times higher in comparison with the typical Ti/Sb-SnO2/PbO2 electrode. It was found that the removal efficiency of COD could be increased from 49% to 69% after 120 min treatment in the presence of 10 mM Cl−1 in the electrolyte. After 6 h of electrolysis, 74% of TOC was removed and 31% and 22% of initial N was transformed into NH4+ and NO3− ions, respectively. And oxalic acid, glyoxylic acid, malonic acid and acetic acid were identified quantitatively as the intermediate products. Finally, it was estimated that the accelerated service life of Ti/TiO2-RNTs/Sb-SnO2/PbO2-ND electrode was approximately three times of Ti/Sb-SnO2/PbO2 electrode. Generally, this study is of great interest for the engineering community to design an efficient electrode material for the wastewater treatment.

Role of p53 mediated miR-23a/CXCL12 pathway in osteogenic differentiation of bone mesenchymal stem cells on nanostructured titanium surfaces.

Titanium surface modification is widely established and has been proven to improve the osseointegration, but the molecular mechanism remains to be fully elucidated. MicroRNAs serve vital roles in the process of regulating osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). In this study, we report that miR-23a was significantly down-regulated in the osteogenic differentiation process of BMSCs on nanostructured titanium surfaces. Elevated miR-23a inhibited osteogenic differentiation of BMSCs, and decreased miR-23a enhanced this process. In addition, we also observed that CXCL12 was a direct target of miR-23a. Knockdown of CXCL12 inhibited nanotube Ti induced-osteogenic differentiation of BMSCs, similar to the effect of upregulation of miR-23a. Finally, p53 was decreased and it regulated miR-23a/CXCL12 axis during nanotube Ti induced-osteogenic differentiation of BMSCs. Therefore, our findings suggest that by targeting CXCL12, miR-23a serves a vital role in osteogenic differentiation of BMSCs cultured on nanostructured titanium surfaces, which may provide novel clinical treatments for osseointegration.

Phelligridin D-loaded oral nanotube titanium implant enhances osseointegration and prevents osteolysis in rat mandible

Poor bone quality and osteolysis are the major causes of implant failure in dentistry. Here, this study tested the effect of phelligridin D-loaded nanotubes titanium (Ti) for bone formation around the dental implants. The purpose of this study was to enhance osseointegration of phelligridin D-loaded implant into the bone for bone formation and prevention of osteolysis. Cell viability, crystal violet staining, Western blot, alizarin red S staining, alkaline phosphatase activity, tartrate-resistant acid phosphatase staining, micro-computed tromography (μ-CT), hematoxylin and eosin (H&E) and immunohistochemical staining were used in vitro and in vivo to test the biocompatibility of phelligridin D. Phelligridin D enhanced osteoblast differentiation and mineralization by increasing bone morphogenic protein-2/7 (BMP-2/7), Osterix, Runx-2, osteoprotegerin (OPG), alkaline phosphatase and inhibited osteoclast differentiation by decreasing receptor activator of nuclear factor kappa-B ligand (RANKL) in MC-3T3 E1 cells. Further, phelligridin D promoted bone regeneration around nanotube Ti implant surface by increasing the levels of BMP-2/7 and OPG in a rat model. Phelligridin D also inhibited osteolysis by suppressing the expression of RANKL. These findings strongly suggest that phelligridin D is a new compound representing a potential therapeutic candidate for implant failure caused by osteolysis and poor bone quality of teeth.

Photoelectrocatalyst of Fe co-doped N-TiO2/Ti nanotubes: Pesticide degradation of thiamethoxam under UV–visible lights

Preparation of titanium dioxide (TiO2) had been carried out by anodizing method that was continued by Nitrogen (N) and Iron (Fe) doping to obtain the Fe-N-TiO2/Ti electrode through sol-gel method. The synthesis of Fe-N-TiO2/Ti by adding NH4Cl as a source of N and Fe(NO3)3 as a source of Fe were prepared by dip-coating technique. The photocurrent response of TiO2/Ti and Fe-N-TiO2/Ti tested in photoelectrocatalyst showed the TiO2/Ti electrode was active in UV light and Fe-N-TiO2/Ti was active in the visible light. The XRD and SEM characterizations result of Fe-N-TiO2/Ti was the forming of anatase crystal and nanotube structure. The FTIR data was indicated the presence of FeO and TiN bonds on the wavenumber of 580cm−1 and 509cm−1, respectively. The degradation result of thiamethoxam pesticide compound in photoelectrocatalyst showed the TiO2/Ti electrode was active on the UV light irradiation with degradation rate constant 0.0436min−1 and Fe-N-TiO2/Ti was active in the visible irradiation with the degradation rate constant 0.0580min−1.

Modified surface morphology of a novel Ti–24Nb–4Zr–7.9Sn titanium alloy via anodic oxidation for enhanced interfacial biocompatibility and osseointegration

The Ti–24Nb–4Zr–7.9Sn titanium alloy (Ti2448) has shown potential for use in biomedical implants, because this alloy possesses several important mechanical properties, such as a high fracture strength, low elastic modulus, and good corrosion resistance. In this study, we aimed to produce a hierarchical nanostructure on the surface of Ti2448 to endow this alloy with favorable biological properties. The chemical composition of Ti2448 (64.0wt% Ti, 23.9wt% Nb, 3.9wt% Zr, and 8.1wt% Sn) gives this material electrochemical properties that lead to the generation of topographical features under standard anodic oxidation. We characterized the surface properties of pure Ti (Ti), nanotube-Ti (NT), Ti2448, and nanotube-Ti2448 (NTi2448) based on surface morphology (scanning electron microscopy and atomic force microscopy), chemical and phase compositions (X-ray diffraction and X-ray photoelectron spectroscopy), and wettability (water contact angle). We evaluated the biocompatibility and osteointegration of implant surfaces by observing the behavior of bone marrow stromal cells (BMSCs) cultured on the surfaces in vitro and conducting histological analysis after in vivo implantation of the modified materials. Our results showed that a hierarchical structure with a nanoscale bone-like layer was achieved along with nanotube formation on the Ti2448 surface. The surface characterization data suggested the superior biocompatibility of the NTi2448 surface in comparison with the Ti, NT, and Ti2448 surfaces. Moreover, the NTi2448 surface showed better biocompatibility for BMSCs in vitro and better osteointegration in vivo. Based on these results, we conclude that anodic oxidation facilitated the formation of a nanoscale bone-like structure and nanotubes on Ti2448. Unlike the modified titanium surfaces developed to date, the NTi2448 surface, which presents both mechanical compatibility and bioactivity, offers excellent biocompatibility and osteointegration, suggesting its potential for use in orthopedic applications.

Effect of TiO2 Nanotube Layers Thickness on Periodontal Ligament Cells

Periodontal ligament cells (PDLCs) remaining in the tooth-extraction socket are involved in osseointegration after immediate implantation; however, their interaction with different implant surfaces has not been investigated. The aim of this study was to compare PDLC growth on substrates composed of differently sized titanium dioxide (TiO2) nanotubes with that on flat Ti. PDLC growth on Ti nanotubes was evaluated in terms of cell adhesion, proliferation, and osteogenic differentiation based on the expression of alkaline phosphatase (ALP), type 1 collage (COL-1), osteopontin (OPN), and Runt-related transcription factor 2 (RUNX2). We found that TiO2 nanotubes of different diameters (30, 70, and 120 nm) manufactured on Ti surface by anodisation had a well-defined structure. PDLCs grown on nanotube layers demonstrated polygonal morphology with more filopodia than those on flat Ti, which was especially evident on the nanotubes of larger diameters. However, cell adhesion and proliferation was the highest on the smallest 30 nm nanotubes. Similarly, mRNA levels of the ALP, COL-1, OPN, and RUNX2 genes increased in PDLCs cultured on 30 nm TiO2 nanotube layers compared to those in the cells grown on 70 nm and 120 nm nanotubes. In conclusion, small diameter (30 nm) nanotube layers can support PDLC adhesion, proliferation, and differentiation better than larger sized nanotubes, and consequently, have higher potential to promote bone formation and integration of an immediate implant.

A novel highly active nanostructured IrO2/Ti anode for water oxidation

IrO2 is one of the most active water oxidant catalysis for the oxygen evolution anode owing to its chemical stability and outstanding catalytic activities, however iridium (Ir) is also one of the rarest metals in the world. In this report, a novel highly active nanostructured IrO2/Ti anode for oxygen evolution reaction (OER) was fabricated by depositing IrO2 nanoparticles onto Ti nanotube substrates. This nanostructured IrO2/Ti anode exhibits comparable oxygen evolution catalytic activities as the traditional IrO2/Ti dimensional stable anode with only 1% iridium consumption of the traditional method. This nanostructured IrO2/Ti anode would be a promising candidate method for fabricating high effective IrO2/Ti anode with low Ir consumption.

Reversible oxygen scavenging at room temperature using electrochemically reduced titanium oxide nanotubes.

A material capable of rapid, reversible molecular oxygen uptake at room temperature is desirable for gas separation and sensing, for technologies that require oxygen storage and oxygen splitting such as fuel cells (solid-oxide fuel cells in particular) and for catalytic applications that require reduced oxygen species (such as removal of organic pollutants in water and oil-spill remediation). To date, however, the lowest reported temperature for a reversible oxygen uptake material is in the range of 200-300 °C, achieved in the transition metal oxides SrCoOx (ref. 1) and LuFe₂O(4+x) (ref. 2) via thermal cycling. Here, we report rapid and reversible oxygen scavenging by Ti(2-x) nanotubes at room temperature. The uptake and release of oxygen is accomplished by an electrochemical rather than a standard thermal approach. We measure an oxygen uptake rate as high as 14 mmol O₂ g(-1) min(-1), ∼2,400 times greater than commercial, irreversible oxygen scavengers. Such a fast oxygen uptake at a remarkably low temperature suggests a non-typical mechanistic pathway for the re-oxidation of Ti(2-x). Modelling the diffusion of oxygen, we show that a likely pathway involves 'exceptionally mobile' interstitial oxygen produced by the oxygen adsorption and decomposition dynamics, recently observed on the surface of anatase.

Optimizing stem cell functions and antibacterial properties of TiO2 nanotubes incorporated with ZnO nanoparticles: experiments and modeling.

To optimize mesenchymal stem cell differentiation and antibacterial properties of titanium (Ti), nano-sized zinc oxide (ZnO) particles with tunable concentrations were incorporated into TiO2 nanotubes (TNTs) using a facile hydrothermal strategy. It is revealed here for the first time that the TNTs incorporated with ZnO nanoparticles exhibited better biocompatibility compared with pure Ti samples (controls) and that the amount of ZnO (tailored by the concentration of Zn(NO3)2 in the precursor) introduced into TNTs played a crucial role on their osteogenic properties. Not only was the alkaline phosphatase activity improved to about 13.8 U/g protein, but the osterix, collagen-I, and osteocalcin gene expressions was improved from mesenchymal stem cells compared to controls. To further explore the mechanism of TNTs decorated with ZnO on cell functions, a response surface mathematical model was used to optimize the concentration of ZnO incorporation into the Ti nanotubes for stem cell differentiation and antibacterial properties for the first time. Both experimental and modeling results confirmed (R2 values of 0.8873–0.9138 and 0.9596–0.9941, respectively) that Ti incorporated with appropriate concentrations (with an initial concentration of Zn(NO3)2 at 0.015 M) of ZnO can provide exceptional osteogenic properties for stem cell differentiation in bone cells with strong antibacterial effects, properties important for improving dental and orthopedic implant efficacy.

Applications of Titania Nanotubes in Bone Biology.

Orthopedic implants, including artificial joints and fracture fixation devices, have helped to restore the physical independence of many patients, thereby improving the quality of their lives. Titania (Ti) and its alloys are better implant materials than stainless steel and Co-Cr alloys owing to their superior mechanical properties and biocompatibility; however, Ti-based implants may sometimes fail, leading to repeated surgeries. With the recent advancements in nanotechnology, the nanosurface modifications of Ti, especially in the form of Ti nanotubes (TNTs), have drastically improved the properties of orthopedic implants. In this review, we have summarized the fabrication of Ti nanotubes by electrochemical anodization and their influence on osteoblast cells and staphylococcus aureus. In addition, we have discussed the corrosion resistance of Ti nanotubes.

Fabrication of nanotube arrays on commercially pure titanium and their apatite-forming ability in a simulated body fluid

In this study, we investigated self-organized TiO2 nanotubes that were grown using anodization of commercially pure titanium at 5V or 10V in NH4F/NaCl electrolyte. The nanotube arrays were annealed at 450°C for 3h to convert the amorphous nanotubes to anatase and then they were immersed in simulated body fluid at 37°C for 0.5, 1, and 14days. The purpose of this experiment was to evaluate the apatite-formation abilities of anodized Ti nanotubes with different tube diameters and lengths. The nanotubes that formed on the surfaces of Ti were examined using a field emission scanning electron microscope, X-ray diffraction, and X-ray photoelectron spectroscope. When the anodizing potential was increased from 5V to 10V, the pore diameter of the nanotube increased from approximately 24–30nm to 35–53nm, and the tube length increased from approximately 590nm to 730nm. In vitro testing of the heat-treated nanotube arrays indicated that Ca-P formation occurred after only 1day of immersion in simulated body fluid. This result was particularly apparent in the samples that were anodized at 10V. It was also found that the thickness of the Ca-P layer increases as the applied potential for anodized c.p. Ti increases. The average thickness of the Ca-P layer on Ti that was anodized at 5V and 10V was approximately 170nm and 190nm, respectively, after immersion in simulated body fluid for 14days.

Fabrication of P- and Ca-doped Ti Nanotube Arrays by Using Anodization

Fabrication of P- and Ca-doped Ti Nanotube Arrays by Using Anodization