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Nanotechnology is constantly advancing in dental science, progressing several features aimed at improving dental implants. An alternative for surface treatment of dental implants is electrochemical anodization, which may generate a nanotubular surface (TiO 2 nanotubes) with antibacterial potential and osteoinductive features. This systematic review and meta-analysis aims to elucidate the possible antibacterial properties of the surface in question compared to the untreated titanium surface. For that purpose, was performed a systematic search on the bases PubMed, Lilacs, Embase, Web Of Science, Cinahl, and Cochrane Central, as well as, manual searches and gray literature. The searches resulted in 742 articles, of which 156 followed for full-text reading. Then, 37 were included in the systematic review and 8 were included in meta-analysis. Fifteen studies revealed significant antibacterial protection using TiO 2 nanotube surfaces, while 15 studies found no statistical difference between control and nanotextured surfaces. Meta-analysis of in vitro studies demonstrated relevant bacterial reduction only for studies investigating Staphylococcus aureus in a period of 6 h. Meta-analysis of in vivo studies revealed three times lower bacterial adhesion and proliferation on TiO 2 nanotube surfaces. TiO 2 nanotube topography as a surface for dental implants in preclinical research has demonstrated a positive relationship with antibacterial properties, nevertheless, factors such as anodization protocols, bacteria strains, and mono-culture methods should be taken into consideration, consequently, further studies are necessary to promote clinical translatability. [Display omitted] • TiO 2 nanotubes as an implant surface topography was systematically revised according to their antibacterial potential. • Nanotubular surfaces revealed to induce antibacterial responses. • Preclinical research showed favorable antibacterial outcomes for TiO 2 nanotubes compared to untreated Ti. • Further research is needed to design complex studies evaluating TiO 2 nanotube surfaces in clinical set. [ABSTRACT FROM AUTHOR]

The direct conversion of atmospheric CO2 into fuel via photocatalysis exhibits significant practical application value in advancing the carbon cycle. In this study, we established an electro-assisted photocatalytic system with dual compartments and interfaces, and coated Ag nanoparticles on the titanium nanotube arrays (TNTAs) by polydopamine modification. In the absence of sacrificial agent and alkali absorption liquid conditions, the stable, efficient and highly selective conversion of CO2 to CO at the gas-solid interface in ambient air was realized by photoelectric synergy. Specifically, with the assistance of potential, the CO formation rates reached 194.9 µmol h-1 m-2 and 103.9 µmol h-1 m-2 under ultraviolet and visible light irradiation, respectively; the corresponding CO2 conversion rates in ambient air were 30% and 16%, respectively. The excellent catalytic effect is mainly attributed to the formation of P-N heterojunction during the catalytic process and the surface plasmon resonance effect. Additionally, the introduction of solid agar electrolytes effectively inhibits the hydrogen evolution reaction and improves the electron utilization rate. This system promotes the development of photocatalytic technology for practical applications and provides new insights and support for the carbon cycle. [ABSTRACT FROM AUTHOR]

Titanium is the most used material for implant production. To increase its biocompatibility, continuous research on new coatings has been performed by the scientific community. The aim of the present paper is to prepare new coatings on the surfaces of the pure Ti Grade 2 and the Ti6Al4V alloy. Three types of coatings were achieved by applying anodization and chemical vapor deposition (CVD) methods: TiO2 nanotubes (TNTs) were formed by anodization, carbon nanotubes (CNTs) were obtained through a metal-catalyst-free CVD process, and a bilayer coating (TiO2 nanotubes/carbon nanostructures) was prepared via successive anodization and CVD processes. The morphology and structure of the newly developed coatings were characterized using SEM, EDX, AFM, XRD, and Raman spectroscopy. It was found that after anodization, the morphology of the TiO2 layer on pure Ti consisted of a "sponge-like" structure, nanotubes, and nano-rods, while the TNTs layer on the Ti alloy comprised mainly nanotubes. The bilayer coatings on both materials demonstrated different morphologies: the pure Ti metal was covered by a layer of nanotubular and nano-rod TiO2 structures, followed by a dense carbon layer decorated with carbon nanoflakes, and on the Ti alloy, first, a TNTs layer was formed, and then carbon nano-rods were deposited using the CVD method. [ABSTRACT FROM AUTHOR]

Thermomechanical and impact properties of isotactic polypropylene nanocomposites reinforced with titania nanotubes (TiNTs) at weight distributions of 0.5, 1, and 1.5 wt% were investigated. The goal of this study was to create a novel iPP‐based nanocomposite filament fused filament fabrication (FFF) with improved thermo‐mechanical and impact properties to enable the creation of more customized geometries. First, TiNTs were chemically functionalized with pimelic acid (PA) to promote the β‐crystalline phase using Ca as anchoring. FTIR results revealed the presence of new bands at 1575 and 1413 cm−1, which were attributed to the anchoring of the PA molecule on the TiNT surface. TEM images of the TiNTs confirmed its tubular morphology before and after the functionalization, while the SEM/EDS analysis showed the good dispersion of carbon which can only come from the organic molecule employed in the functionalization. The nano‐reinforcements were incorporated by extrusion generating a filament to produce 3D‐printed specimens. The efficacy of the modified reinforcement as a β‐crystalline phase promoter was evaluated by wide‐angle x‐ray diffraction. The nanocomposite with 1% modified TiNTs showed the highest β‐crystal promotion with a kβ‐index of 89% while the nanocomposites reinforced with unmodified TiNTs reached only 15%. Furthermore, the thermomechanical and impact properties were characterized by dynamic mechanical analysis and Izod. In the first, the storage modulus (E′) was higher than the raw iPP for all nanocomposites, with an increase of about 148% and 107%, while the nanocomposite with a high percentage of β‐crystal showed an increase of 183% in the impact strength properties. A shift of Tg to higher temperatures was attributed to better interfacial interactions polymer/nano‐reinforcement because of the functionalization. The modified nano‐reinforcement was able to generate a 3D‐printed nanocomposite with higher stiffness and impact strength properties than the raw iPP. [ABSTRACT FROM AUTHOR]

Titanium dioxide nanotubes (TNTs) have been extensively researched for their enhanced biomedical characteristics, including biocompatibility, cell apposition, and growth morphology. However, there is a significant concern in metallic medical devices owing to micro-movements between implants and bone in aggressive environments due to wear and corrosion synergies, leading to adverse body responses and implant failure. In this study, TNTs on Commercially Pure titanium (C.P. Ti) with three different thickness layers were grown to correlate their corrosion and wear behavior. Initially amorphous after anodization, TNTs underwent annealing at 450 °C for 2 h to transform the distorted, into a crystalline structure. The characterization included X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray (EDX), X-ray Photoelectron Spectroscopy (XPS), and contact profilometry. Potentiodynamic polarization (PD) and tribocorrosion tests were conducted in Simulated Body Fluid Electrolyte (SBF). SEM micrographs showed TNT thickness layers of 314, 691, and 5280 nm, and X-ray Diffraction showed anatase transformation post-annealing. Results confirmed a significant influence of TNT thickness layers on corrosion and tribocorrosion properties, with higher current density obtained from PD for thicker TNTs layers, associated with surface fluorine content. During tribocorrosion, annealed samples demonstrated lower corrosion tendency, potential drop, and coefficient of friction. Morphology of worn surfaces and volumetric wear rate varied with TNT thickness layer and thermal treatment.

The success of titanium dental implants relies on osseointegration, the load‐bearing connection between bone tissue and the device that, in contact osteogenesis, comprises the deposition of bony cement line matrix onto the implant surface. Titanium dioxide nanotubes (NTs) are considered a promising surface for improved osseointegration, yet the mechanisms of cement line integration with such features remains elusive. Herein, we illustrate cement line deposition into NTs on the surface of titanium implants with two underlaying microstructures: a machined surface or a blasted/acid etched surface placed in the tibiae of Wistar rats. After retrieval, scanning electron microscopy of tissue reflected from the implant surface indicated minimal incursion of the cement line matrix into the NTs. To investigate this further, focused ion beam was utilized to prepare cross‐sectional samples that could be characterized using scanning transmission electron microscopy. The cement line matrix covered NTs regardless of underlying microstructure, which was further confirmed by elemental analysis. In some instances, cement line infiltration into the NTs was noted, which reveals a mechanism of nanoscale anchorage. This study is the first to demonstrate cement line deposition into titanium NTs, suggesting nano‐anchorage as a mechanism for the success of the NT modified surfaces in vivo. [ABSTRACT FROM AUTHOR]

The present in vitro study evaluated the effect of titanium nanotubes (nTiO2) application on high translucent zirconia (Copra Supreme, Whitepeaks) on shear bond strength values with different self-adhesive resin cements (Panavia V5, G-Cem One, and Variolink Esthetic DC). One hundred and forty-eight specimens were prepared and randomly divided into four groups (n = 37) according to surface treatment groups (air-abraded sintered zirconia, air-abraded pre-sintered zirconia, application of nTiO2 on zirconia, and application of nTiO2 on air-abraded zirconia). nTiO2 were produced by alkaline hydrothermal synthesis, mixed with isopropyl alcohol (50 wt%), and applied on pre-sintered zirconia. The surface roughness (Ra) was examined. Sintered surfaces were characterized by field emission scanning electron microscope (Fe-SEM), and energy-dispersive X-ray spectroscopy (EDS) analysis. Surface treatment groups were randomly divided into three subgroups according to self-adhesive resin cement (n = 12). Luting procedures were performed and specimens were stored in water at 21 °C for 6 months before the shear bond strength test. Data were analyzed by one-way ANOVA and two-way ANOVA. Fe-Sem images and EDS confirmed the incorporation of nTiO2 on zirconia. Surface treatment methods affected the Ra of zirconia (p <.001). Surface treatment method (p =.013) and self-adhesive resin cement (p <.001) affected shear bond strength values. The lowest shear bond strength values were achieved in applied nTiO2 on high translucent zirconia specimens (p <.05). The lowest shear bond strength values were determined in the Variolink Esthetic DC group (p <.05). Application of nTiO2 on air-abraded high translucent zirconia surface had no significant effect on the shear bond strength (p >.05). [ABSTRACT FROM AUTHOR]

Abstract Severe lesions in vessels need to be treated with implantable interventional devices such as vascular stents, which should be anti‐coagulantion, anti‐proliferation and promoting endothelialisation. Nitric oxide (NO), as a physiological gas signalling molecule, play an important role in revascularisation. Catalysing the release of NO from endogenous donors has already been widely favoured to treatment strategy for lesioned vessels. In this work, a series of copper‐loaded coatings (titanium nanotube (TNT)/PDA‐Cu) was fabricated by TNTs combined with polydopamine and ions, which achieve controlled in situ catalytic release of NO. This strategy could effectively immobilised copper ions on TNTs, and promoted the proliferation of endothelial cells and inhibited growth of smooth muscle cells (SMCs) via the performance of NO, as well as restrain the platelet adhesion. With the multiple function, TNT/PDA‐Cu provides a promise approach for promoting endothelialisation, anti‐coagulation and inhibition of SMC proliferation via copper‐loaded coatings on TNTs.

As the consumption of implants increases, so do the requirements for individual types of implants, for example, improved biocompatibility or longevity. Therefore, the nano‐modification of the titanium surface is often chosen. The aim was to characterize the modified surface with a focus on medical applications. The titanium surface was modified by the anodic oxidation method to form nanotubes. Subsequently, the material was characterized and analyzed for medical applications—surface morphology, surface wettability, chemical composition, and release of ions into biological fluids. A human gingival fibroblasts (HGFb) cell line was used in the viability study. A homogeneous layer of nanotubes of defined dimensions was formed on the titanium surface, ensuring the material's biocompatibility—the preparation conditions influence the resulting properties of the nanostructured surface. Nanostructured titanium exhibited more suitable characteristics (e.g., wettability, roughness, ion release) for biological applications than compared to pure titanium. It was possible to understand the behavior of the modified layer on the titanium surface and its effect on cell behavior. Another contribution of this work is the combination of material characterization (ion release) with the study of cytocompatibility (direct contact of cells with metals). [ABSTRACT FROM AUTHOR]

Severe lesions in vessels need to be treated with implantable interventional devices such as vascular stents, which should be anti‐coagulantion, anti‐proliferation and promoting endothelialisation. Nitric oxide (NO), as a physiological gas signalling molecule, play an important role in revascularisation. Catalysing the release of NO from endogenous donors has already been widely favoured to treatment strategy for lesioned vessels. In this work, a series of copper‐loaded coatings (titanium nanotube (TNT)/PDA‐Cu) was fabricated by TNTs combined with polydopamine and ions, which achieve controlled in situ catalytic release of NO. This strategy could effectively immobilised copper ions on TNTs, and promoted the proliferation of endothelial cells and inhibited growth of smooth muscle cells (SMCs) via the performance of NO, as well as restrain the platelet adhesion. With the multiple function, TNT/PDA‐Cu provides a promise approach for promoting endothelialisation, anti‐coagulation and inhibition of SMC proliferation via copper‐loaded coatings on TNTs. [ABSTRACT FROM AUTHOR]

In present work, the effect of titania (TiO2) nanotubes formation incorporated with chitosan-58S bioactive glass (TNT/Chitosan-58S BG) on physiochemical properties of titanium substrate was studied. Samples were characterized by Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Corrosion behavior of the coated samples was investigated in Ringer solution through Tafel polarization and electrochemical impedance spectroscopy measurements. Results represented that TiO2 nanotubes orderly formed on titanium substrate through electrochemical anodizing process. Moreover, Chitosan-58S BG coating was formed on the TNT layer with appropriate adhesion strength, owing to the mechanical interlocking. Variation of applied voltage (25 and 30 V) and duration of anodizing process (30, 60 and 120 min) resulted in the formation of TiO2 nanotubes with various diameters in the range of 89–99 nm. Furthermore, electrochemical evaluations illustrated that the presence of titania nanotubes and Chitosan-58S BG on Ti substrate significantly ameliorated the corrosion resistance of Titanium substrate through reducing corrosion current density (3.486 vs. 2.854 µA cm− 2), as well as, increasing total resistance (40.417 vs. 96.875 kΩ cm2). In addition, our study revealed that the surface hardness of Ti substrate improved after two step surface treatments. In summary, appropriate mechanical and electrochemical characteristics make the TNT/Chitosan-58S BG coating, a proper choice for biomedical applications. [ABSTRACT FROM AUTHOR]

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Photocatalytic CO 2 conversion, in general, requires the incorporation of expensive and noble materials to achieve a highly efficient conversion rate. Herein, the TNT/NiO/CQD ternary nanocomposites without any expensive materials and material modification are fabricated for the demonstration of efficient and economically affordable photocatalytic CO 2 conversion, to our best knowledge, for the first time. The TNT-based ternary photocatalysts are successfully prepared by a simple anodization and immersion process. The TNT/NiO/CQD ternary nanocomposites produce 1.47 μmol·cm-2·h-1 (≈ c.a. 2834 μmol·g-1·h-1) of CH 4 as the sole product under AM 1.5 illumination. This is five times higher performance than that of bare TNT and the performance is comparable to that of any other TiO 2 -based unitary, binary, or ternary photocatalysts. This highly enhanced performance results from effective junction formation between TNT and NiO NP, and the dual role of CQDs as a light absorber and charge transporter/collector in the system. The formation of Z-scheme at the TNT/NiO interface leads to efficient charge transfer via a TiO 2 /NiO bond. The light absorption of the photocatalysts is enhanced and extended by decorated CQDs due to their small band gap. The charge transfer and collection are further improved by charge depletion at the TNT/CQD interface and the charge transfer at the NiO/CQD interface. This work provides a possible model for the realization of efficient and economically affordable photocatalytic CO 2 conversion. [ABSTRACT FROM AUTHOR]

Surface modification of titanium has been a hot topic to promote bone integration between implants and bone tissue. Titanium dioxide nanotubes fabricated on the surface of titanium by anodic oxidation have been a mature scheme that has shown to promote osteogenesis in vitro. However, mechanisms behind such a phenomenon remain elusive. In this study, we verified the enhanced osteogenesis of BMSCs on nanotopographic titanium in vitro and proved its effect in vivo by constructing a bone defect model in rats. In addition, the role of the mechanosensitive molecule Yap is studied in this research by the application of the Yap inhibitor verteporfin and knockdown/overexpression of Yap in MC3T3-E1 cells. Piezo1 is a mechanosensitive ion channel discovered in recent years and found to be elemental in bone metabolism. In our study, we preliminarily figured out the regulatory relationship between Yap and Piezo1 and proved Piezo1 as a downstream effector of Yap and nanotube-stimulated osteogenesis. In conclusion, this research proved that nanotopography promoted osteogenesis by increasing nuclear localization of Yap and activating the expression of Piezo1 downstream.

Background: The formation of a nanotube layer on a titanium nanotube (N-Ti) plate facilitates an active reaction between bone cells and the material surface via efficient delivery of the surface materials of the dental implant into the tissues. Studies have reported that Korean Red Ginseng extracts (KRGEs) are involved in a variety of pharmacological activities: we investigated whether implantation with a KRGE-loaded N-Ti miniimplant affects osteogenesis and osseointegration. Methods: KRGE-loaded nanotubes were constructed by fabrication on pure Ti via anodization, and MC3T3-E1 cells were cultured on the N-Ti. N-Ti implants were subsequently placed on a rat's edentulous mandibular site. New bone formation and bone mineral density were measured to analyze osteogenesis and osseointegration. Results: KRGE-loaded N-Ti significantly increased the proliferation and differentiation of MC3T3-E1 cells compared with cells on pure Ti without any KRGE loading. After 1–4 weeks, the periimplant tissue in the edentulous mandibular of the healed rat showed a remarkable increase in new bone formation and bone mineral density. In addition, high levels of the bone morphogenesis protein-2 and bone morphogenesis protein-7, besides collagen, were expressed in the periimplant tissues. Conclusion: Our findings suggest that KRGE-induced osteogenesis and osseointegration around the miniimplant may facilitate the clinical application of dental implants.

The entire route from anodic oxidation and surface characterization, including in vitro experiments and finally in vivo osseointegration assays were performed with the aim to evaluate nanotubular and crystalline annealed titanium oxides as a suitable surface for grade 2 titanium permanent implants. Polished titanium (T0) was compared with anodized surfaces obtained in acidic media with fluoride, leading to an ordered nanotubular structure of titanium oxide on the metal surface, characterized by tube diameter of 89 ± 24 nm (Tnts). Samples were thermally treated in air (TntsTT) to increase the anatase crystalline phase on nanotubes, with minor alteration of the structure. Corrosion tests were performed to evaluate the electrochemical response after 1, 14, and 28 days of immersion in simulated body fluid. Based on the in vitro results, heat‐treated titanium nanotubes (TntsTT) were selected as a promissory candidate to continue with the osseointegration in vivo assays. The in vivo results showed no major improvement in the osseointegration process when compared with untreated Ti after 30 days of implantation and there also was a lower increase in the development of new osseous tissue. [ABSTRACT FROM AUTHOR]

[Display omitted] • CuMnFeO x /TiO 2 NTs catalyst were prepared with titanium dioxide nanotubes as support. • CuMnFe/TiO 2 NTs exhibited excellent performance in the removal of CO and NO. • The addition of TiO 2 NTs can enhance the catalyst's N 2 selectivity. • Reaction mechanisms of NH 3 -SCR and CO oxidation were explored by in situ DRIFTS. NOx and CO are the primary air pollutants emitted from sintering flue gas, and their effective treatment is crucial. However, achieving good N 2 selectivity with the CuMnFe composite metal oxide catalyst alone is challenging due to its oxidizing nature. Hence, in this study, titanium dioxide nanotubes were employed as carriers for the catalyst. CuMnFe composite metal oxide catalysts supported on titanium dioxide nanotubes were prepared using the co-precipitation method. The optimized catalysts demonstrated excellent performance, maintaining over 90% conversion of NO x and CO at low temperatures ranging from 120 to 200 ℃. Furthermore, significant improvement in N 2 selectivity was achieved using these catalysts. Characterization results revealed several positive effects of incorporating titanium dioxide nanotube carriers into the catalyst. Firstly, it efficiently reduced the mobility of adsorbed oxygen on the catalyst surface, thus decreasing its oxidation capacity. Secondly, the addition of carriers helped balance the acidity on the catalyst surface, leading to an increase in Lewis acid sites. These modifications in the catalyst's surface properties proved advantageous for the selective catalytic reduction reaction. Moreover, the mechanisms of NH 3 -SCR and CO oxidation over the catalysts were extensively studied using DRIFTS. The results demonstrated that the CO oxidation reaction followed the Mars-van Krevelen mechanism, with a competitive adsorption relationship observed between O 2 and CO at the active sites. On the other hand, the NH 3 -SCR reaction primarily followed the Eley-Rideal mechanism, with minimal occurrence of the Langmuir-Hinshelwood mechanism in the SCR reaction. The presence of NH 3 inhibits CO adsorption at the active site, resulting in decreased CO oxidation performance in the NH 3 -SCR-coupled CO oxidation reaction at low temperatures. Nevertheless, NH 3 -SCR can enhance NO conversion by utilizing some of the latent heat generated from the exothermic CO oxidation. [ABSTRACT FROM AUTHOR]

Liu W, Su P, Gonzales III A, et al. Int J Nanomedicine. 2015;10(1):1997–2019. The Editor and Publisher of International Journal of Nanomedicine wish to retract the published article. Concerns were raised regarding the duplication of figures and results with those from an earlier publication, Liu et al, 2014 (https://doi.org/10.1039/C4NR01531B), by the authors. Specifically: Figures 1B and 1b appear to have been published previously as Figures 1B and 1b from Liu et al, 2014. Results from Table 2 had previously been published in Table 2 from Liu et al, 2014. Parts of Figure 2A appear to have been previously published in Figure 4 from Liu et al, 2014. Figures 2B and 2C appear to have been previously published as Figures 5a and 5b in Liu et al, 2014, respectively. Figure S1B appears to have been duplicated with Figure 3b from Liu et al, 2014, albeit with some adjustment to the image’s orientation. It was acknowledged the earlier Liu et al, 2014 publication had been referenced, however the authors failed to properly cite this article as the source of the figures and results described above. In addition, the authors were unable to provide a satisfactory justification to the Editor for the need to republish these same figures and results. The Editor requested for the article to be retracted. The authors do not agree with the decision to retract the article. Our decision-making was informed by our policy on publishing ethics and integrity and the COPE guidelines on retraction. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as “Retracted”. This retraction relates to this paper

The aim in the present study was to explore the potential application of titanium nanotubes developed in the Ti–24Zr–10Nb–2Sn alloy, as drug delivery systems to prevent bacterial infections in medical devices. A nanotubular oxide layer was synthesized by electrochemical anodizing on the Ti–24Zr–10Nb–2Sn superelastic alloy and the electrical variables that control the growth at constant potential were determined. Scanning electron microscopy (SEM) showed that the nanostructures show a positive linear growth as a function of the applied potential, the superficial analysis carried out by X-ray photoelectron spectroscopy (XPS) showed different states of valence evidencing the presence of TiO2, Nb2O5, SnO2, and ZrO2. FTIR spectra confirm the presence of the antibiotic gentamicin in the Ti–24Zr–10Nb–2Sn nanotubes. The developed nanostructures were evaluated in a phosphate buffer solution (PBS) as a controlled release system of antibiotics. It was observed by bacteriological tests that the nanostructured morphology in combination with the chemical composition has bacteriostatic properties; while the release of the antibiotic-loaded inside the nanotubes had a bactericidal effect. The results showed that it is possible to grow and control the morphology of the developed nanostructures on Ti–24Zr–10Nb–2Sn, which can be used for orthopedic purposes to transport and control the local release of molecules like antibiotics at the site of interest and thus prevent postoperative infections. [ABSTRACT FROM AUTHOR]

The sorption of Ca2+ on the surface of TiO2 nanoparticles in a saturated solution of Ca(OH)2 was observed by rapid heat evolution compared to the reference sample using isothermal calorimetric analysis. In addition to that, the interaction of TiO2 nanoparticles with a saturated Ca(OH)2 solution under hydrothermal conditions (40, 80, and 120°C) in an autoclave was carried out as well. Perovskite formed as a result of interaction between TiO2 and saturated Ca(OH)2 under temperatures of 80 and 120°C. Similarly, the formation of perovskite was found along with a hydration product when tricalcium silicate was hydrated in the presence of TiO2 nanotubes under hydrothermal condition (120°C). X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to investigate the presence of perovskite. [ABSTRACT FROM AUTHOR]

Titanium nanotubes (TNT) possess unique properties owing to their high surface-to-volume ratio and thus utilized in various applications. For the fabrication of TNT, anodization method is preferred due to its simplicity and low cost. In this study, titanium nanotubes were produced via anodization method and the effect of various parameters such as applied voltage, anodization time, and concentration of H 3 PO 4 in the electrolyte mixture (i.e. NH 4 F and ethylene glycol) on the average inner diameter of the TNT were investigated. A novel methodology for machining titanium with electrochemical micromachining (ECMM) has been put forward with modification in the topography by producing TNT on the titanium surface. The optimum parameters for producing well-ordered uniform TNT arrays have been found to be 3 hours of anodization with an electrolyte mixture of 0.3 M H 3 PO 4 and 0.3 M NH 4 F at 30 V potential. The anodization with these optimum parameters resulted in the uniform TNT arrays with an average inner diameter of 48±5 nm. ECMM has been demonstrated on the titanium surface with and without TNTs. It is concluded that the dissolution along the depth direction is higher than the radial dissolution for the titanium surface with TNTs. In summary, the surface with TNTs aids the ECMM machining performance of titanium. [ABSTRACT FROM AUTHOR]

(1) Background: Implantation of metal-based scaffolds is a common procedure for treating several diseases. However, the success of the long-term application is limited by an insufficient endothelialization of the material surface. Nanostructured modifications of metal scaffolds represent a promising approach to faster biomaterial osteointegration through increasing of endothelial commitment of the mesenchymal stem cells (MSC). (2) Methods: Three different nanotubular Ti surfaces (TNs manufactured by electrochemical anodization with diameters of 25, 80, or 140 nm) were seeded with human MSCs (hMSCs) and their exosomes were isolated and tested with human umbilical vein endothelial cells (HUVECs) to assess whether TNs can influence the secretory functions of hMSCs and whether these in turn affect endothelial and osteogenic cell activities in vitro. (3) Results: The hMSCs adhered on all TNs and significantly expressed angiogenic-related factors after 7 days of culture when compared to untreated Ti substrates. Nanomodifications of Ti surfaces significantly improved the release of hMSCs exosomes, having dimensions below 100 nm and expressing CD63 and CD81 surface markers. These hMSC-derived exosomes were efficiently internalized by HUVECs, promoting their migration and differentiation. In addition, they selectively released a panel of miRNAs directly or indirectly related to angiogenesis. (4) Conclusions: Preconditioning of hMSCs on TNs induced elevated exosomes secretion that stimulated in vitro endothelial and cell activity, which might improve in vivo angiogenesis, supporting faster scaffold integration.

• Silver/titanium nanoparticles used as biocidal treatment for cultural heritage. • Aesthetical compatibility of treatments measured by colorimetric technique. • Detection and depth penetration of the treatments analysed by LIBS. • Capability of the treatments to inhibit the biofouling formation. One of the main problems in the conservation of historical buildings and archaeological sites is the one caused by biodeterioration. Biopatina, biocrust or biofouling generate aesthetical changes and induce degradation processes within the stone matrix. In this work, three treatments based on silver nanoparticles and silver/titanium dioxide nanocomposites have been studied as potential biocides for limestones: citrate-stabilized silver nanoparticles, silver/TiO 2 nanocomposites and citrate-stabilized silver/TiO 2 nanocomposites. These treatments were synthesized following a bottom-up method, using or not a stabilizing agent (citrate), and have been characterized by UV-Visible spectrophotometry, Dynamic Light Scattering and Raman spectroscopy. These treatments were applied on limestones from three different Spanish quarries located in Utrera (Seville), El Puerto de Santa María (Cadiz) and Novelda (Alicante). The aesthetical modification of limestone surfaces was studied by colorimetric techniques and the effectiveness of protection against biofouling formation was tested using an accelerated biofouling growth assay. The best results were obtained for the treatments based on citrate-stabilized silver nanoparticles. The effectiveness of the treatments depends on their penetration depth in the stone matrix and in this study, we have used Laser Induced Breakdown Spectroscopy to determine the depth profiles of nanocomposite presence in the stone matrix. Our results demonstrate that nanocomposites based on citrate-stabilized silver nanoparticles can be useful for the treatment of historical buildings and archaeological sites made of limestone, without producing high colour increments. Additionally, we have demonstrated the suitability of Laser Induced Breakdown Spectroscopy for the detection of silver/TiO 2 nanocomposites and for the generation of depth profiles. [ABSTRACT FROM AUTHOR]

In this work we present a comparative study of three methods in obtaining samples at low cost. The samples obtained are nanopaticules of Iron oxide, copper oxide and Titanium nanotubes. The first two were obtained by the Sol-Gel, polymeric precursors and the third sample by the chemical anodization method. The samples were characterized by optical methods such as Raman, X-rays and scanning electron microscopy. The methods used to obtain the samples are chemical methods from which excellent samples can be obtained at a low cost and with the use of simple laboratories, especially in Colombia where the investment in research laboratories is low so far. [ABSTRACT FROM AUTHOR]

Highlights • A highly conductive electroactive polyaniline (PANI) was electrodeposited uniformly on titania nanotubes (TNTs) substrate. • Titania nanotubes-polyaniline (TNTs-PANI) showed antibacterial activity and corrosion resistivity. • The biointerface TNTs-PANI was used as basal substrate for PC12 cells regeneration and differentiation. • The flexible TNTs-PANI substrate accelerated the neurites outgrowth of PC12 cells. Abstract Biologically active conjugated polymers, for example polyaniline (PANI), have drawn attention as emerging materials for applications in bio-medical implant devices, due to their inherent abilities with regard to charge-carrier properties, and their ability to immobilize biomolecules or proteins. Herein, we report an electrocoating of PANI on titania nanotubes (TNTs) via electrochemical oxidation of aniline with PANI layers of appropriate thickness (∼274 nm). Uniform titanium oxide nanotubes were first developed from titanium (Ti) foil through an anodization process, followed by calcination to obtain high purity TNTs vertically aligned on a Ti substrate. These had a large surface area, controllable tube height and diameter, and were highly biocompatible, and doping with PANI further improved their properties, like being antibacterial, having a lower charge transfer resistance (22.51 Ω) and strong anti-corrosion behavior (E corr ∼ − 184 mV, I corr ∼ 9.7 × 10−7 Amp). In vitro experiments revealed that the cellular functions of PC12 and S42 cells on TNTs-PANI scaffolds show characteristic improvement in proliferation and differentiation owning to approach neuronal cells activation associated with axonal growth and migration in the peripheral nervous system (PNS). Thus, the flexible bioactive substrate is capable of stimulating neuronal cells, and can inspire neural transduction through direct neural interfaces. [ABSTRACT FROM AUTHOR]

Abstract: In this study, H2Ti2O5·H2O nanotubes (TNTs) prepared through hydrothermal synthesis and TiO2 used as a raw material were deposited on the surface of bamboo fibre materials through a layer-by-layer (LBL) self-assembly technique to reduce flammability. Scanning electron microscopy indicated that the TNTs were successfully loaded onto the bamboo surface, and their content was dependent on the number of assembled bilayers. Cone calorimetry results showed that the flame retardant performance of the coated bamboo fibre materials improved significantly. As the number of the assembled bilayers increased, performance was further enhanced. When the number of TNTs bilayers was 9, the time to ignition of the bamboo fibre materials was extended from 29.5 s for raw bamboo fibre (RBF) materials to 36.8 s for LBL9. The average heat release rate, total heat release and peak specific extinction area of the fibre materials decreased from 55.67 MJ/m2 (RBF) to 35.28 MJ/m2 (LBL9), and their fire performance index increased from 0.123 m2 s/kW (RBF) to 0.161 m2 s/kW (LBL9). Differential scanning calorimetry and thermogravimetry results demonstrated that the thermal oxidation and decomposition temperatures of bamboo fibre materials increased from 241.4 °C and 217 °C (RBF) to 311.3 °C and 274 °C (LBL9), respectively.Graphical abstract: [ABSTRACT FROM AUTHOR]

Abstract Dexamethasone, an anti-inflammatory drug, was intercalated in both Zn/Al-NO 3 and Zn/Al-CO 3 layered double hydroxides with three different LDH/DEXA molar ratios through ion-exchange technique. Then the maximum added drug nanohybrid (NL-1D) deposited into nanotubes of anodized titanium (ATS-NL-1D). The X-ray diffraction (XRD) demonstrated that dexamethasone anions are accommodated within the interlayer space of Zn/Al-NO 3 LDHs, with the d spacing of 8.9 Å which became 21.215 Å after intercalation (NL-1D). However, it confirmed that dexamethasone anions only settled on the surface of Zn/Al-CO 3 LDHs and we only demonstrated Zn/Al-CO 3 data to prove that drug anions never intercalated into the interlayer space of these LDHs. The Fourier transform infrared spectroscopy (FTIR) also supported the formation of Zn/Al-NO 3 LDHs and confirmed unsuccessful intercalation of the drug in Zn/Al-CO 3 LDHs, therefore we continued our work with Zn/Al-NO 3 LDHs. Thermal analysis (STA) showed that nanohybrids are more thermally stable than the drug alone. Furthermore, it demonstrated that dexamethasone loading for NL-1D was around 12%. In-vitro release study of LDH-DEXA nanohybrids suggested a considerable reduction in release rate due to the incarceration of drug molecules inside nanohybrids. Release rate showed even more reduction from ATS-NL-1D, because of entanglement of nanohybrid particles inside nanotubes of anodized titanium which justified the anodization process for implant application. Cell adhesion and viability studies revealed that ATS-NL-1D not only wasn't toxic but also the osteoblast cells viability was more than 80% on these sheets. All in all, this work demonstrated that ATS-NL-1D is a suitable candidate for bone implant applications. Graphical abstract fx1 Highlights • Intercalation expanded the interlayer spacing of nitrate LDHs from 8.9 Å to 21.215 Å. • Amount of drug in nitrate layered double hydroxide was estimated to be 12%. • Nanohybrid deposition on anodized titanium decreased the release time. • Osteoblast cell viability was more than 80% on samples with great cell adhesion. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Exosomes are extracellular nanovesicles that play an important role in cellular communication. The modulatory effects of bone morphogenetic protein 2 (BMP2) on macrophages have encouraged the functionalization of scaffolds through the integration of the exosomes from the BMP2-stimulated macrophages to avoid ectopic bone formation and reduce adverse effects. To determine the functionality of exosomal nanocarriers from macrophages after BMP2 stimulation, we isolated the exosomes from Dulbecco's modified Eagle's medium (DMEM)- or BMP2-stimulated macrophages and evaluated their effects on osteogenesis. Morphological characterization of the exosomes derived from DMEM- or BMP2-treated macrophages revealed no significant differences, and the bone marrow-derived mesenchymal stromal cells showed similar cellular uptake patterns for both exosomes. In vitro study using BMP2/macrophage-derived exosomes indicated their beneficial effects on osteogenic differentiation. To improve the bio-functionality for titanium implants, BMP2/macrophage-derived exosomes were used to modify titanium nanotube implants to favor osteogenesis. The incorporation of BMP2/macrophage-derived exosomes dramatically increased the expression of early osteoblastic differentiation markers, alkaline phosphatase (ALP) and BMP2, indicative of the pro-osteogenic role of the titanium nanotubes incorporated with BMP2/macrophage-derived exosomes. The titanium nanotubes functionalized with BMP2/macrophage-derived exosomes activated autophagy during osteogenic differentiation. In conclusion, the exosome-integrated titanium nanotube may serve as an emerging functional material for bone regeneration. Statement of Significance The clinical application of bone morphogenetic protein 2 (BMP2) is often limited by its side effects. Exosomes are naturally secreted nanosized vesicles derived from cells and play an important role in intercellular communication. The contributions of this study include (1) the demonstration of the potential regulatory role of BMP2/macrophage-derived exosomes on the osteogenic differentiation of mesenchymal stromal cells (MSCs); (2) fabrication of titanium nanotubes incorporated with exosomes; (3) new insights into the application of titanium nanotube-based materials for the safe use of BMP2. [ABSTRACT FROM AUTHOR]

Abstract To significantly improve the solar harvesting and electron transportation, Bi 2 S 3 /BiOI p-n heterojunctions were successfully formed on the surface of TiO 2 nanotube arrays (TiO 2 NTs/Bi 2 S 3 -BiOI) by a simple solvothermal method, and the morphology, composition and photoelectrochemical property of the TiO 2 NTs/Bi 2 S 3 -BiOI were investigated by adjusting the concentration ratio of sulphur/iodonium. TiO 2 NTs/Bi 2 S 3 -BiOI nanosheets and nanorods were prepared, and the self-assembled microflowers were also observed. The results indicated that flower-like TiO 2 NTs/Bi 2 S 3 -BiOI showed high visible light absorption, photocurrent density and rapid photoelectrocatalytic removal of organic dyes and Cr(VI). The growth and photocatalytic mechanism were proposed to illuminate the high photoelectrochemical performances. The excellent photoelectrochemical activities drive the TiO 2 NTs/Bi 2 S 3 /BiOI being superior environmental and energy materials in the applications of wastewater purification and solar cells. [ABSTRACT FROM AUTHOR]

The main disadvantage of the implants is the associated infections. Therefore, in the long term, the possibility of improving the antibacterial capacity of different types of implants (dental, orthopedic) is being researched. The severity of the problem lies in the increasing bacterial resistance and finding appropriate alternative treatments for infectious diseases, which is an important research field nowadays. The purpose of this review is to draw a parallel between different studies analyzing the antibacterial activity and mechanism of silver nanoparticles (NP Ag) deposited on the titanium nanotubes (NTT), as well as the analysis of the NP Ag toxicity. This review also provides an overview of the synthesis and characterization of TiO2-derived nanotubes (NT). Thus, the analysis aims to present the existing knowledge to better understand the NP Ag implants benefits and their antibacterial activity.

Ying Yang,1 Hai-yong Ao,1 Sheng-bing Yang,1 Yu-gang Wang,1 Wen-tao Lin,2 Zhi-feng Yu,1 Ting-ting Tang1 1Shanghai Key Laboratory of Orthopedic Implants, Department of Orthopedic Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, 2Department of Orthopedics, Fuzhou Second Hospital, Affiliated Hospital of Xiamen University, Fuzhou, People’s Republic of China Abstract: Titanium-based implants have been widely used in orthopedic surgery; however, failures still occur. Our in vitro study has demonstrated that gentamicin-loaded, 80 nm-diameter nanotubes possessed both antibacterial and osteogenic activities. Thus, the aim of this study was to further investigate the in vivo anti-infection effect of the titanium implants with gentamicin-loaded nanotubes. Thirty-six male Sprague Dawley rats were used to establish an implant-associated infection model. A volume of 50 µL Staphylococcus aureus suspension (1×105 CFU/mL) was injected into the medullary cavity of the left femur, and then the titanium rods without modification (Ti), titanium nanotubes without drug loading (NT), and gentamicin-loaded titanium nanotubes (NT-G) were inserted with phosphate-buffered saline-inoculated Ti rods as a blank control. X-ray images were obtained 1 day, 21 days, and 42 days after surgery; micro-computed tomography, microbiological, and histopathological analyses were used to evaluate the infections at the time of sacrifice. Radiographic signs of bone infection, including osteolysis, periosteal reaction, osteosclerosis, and damaged articular surfaces, were demonstrated in the infected Ti group and were slightly alleviated in the NT group but not observed in the NT-G group. Meanwhile, the radiographic and gross bone pathological scores of the NT-G group were significantly lower than those of the infected Ti group (P

A one-step process combining the photocatalytic degradation of radionuclide complexes and the adsorption of liberated radionuclides on titanium dioxide nanotubes was developed and tested for the purification of aqueous waste produced from chemical decontamination of nuclear power plant circuit components. Among the tested forms of TiO2, only nanotubes exhibit both high photocatalytic activity and sorption ability, which support their application in a one-step purification process. The obtained results indicate that the photocatalytic degradation of complexes followed by the sorption of the radionuclides onto TiO2 nanotubes offers a promising route for treating spent decontamination fluids.

TiO2 nanotube films obtained by anodization have shown great promise as biomaterials. In the present work, we report on the corrosion behaviors of titanium (Ti) with various TiO2 nanotubes prepared by using controlled anodization procedures. Special emphasis is put on the impact of film morphologies on the corrosion resistance of the Ti substrate. The corrosion behaviors of Ti with different nanotube films were studied in artificial saliva using open-circuit potential measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy techniques. Ti covered by TiO2 nanotube films showed the markedly enhanced corrosion resistance properties compared to bare Ti. The existence of the compact oxide layer formed in a fluoride-free electrolyte was found to be beneficial for improving corrosion resistance properties. Besides, the TiO2 nanotube films obtained by two-step anodization had better corrosion resistance than those obtained by single-step anodization, though they used the identical anodization parameters. [ABSTRACT FROM AUTHOR]

Infection associated with orthopedic implants is the chief cause of implant failure. An important consideration to prevent the infection at implants is to inhibit the biofilm formation for the initial 6 h. Therefore, we fabricated hyaluronidase-sensitive multilayers of chitosan (Chi)/sodium hyaluronate-lauric acid (SL) onto the surface of bone morphogenetic protein 2 (BMP2) loaded titanium nanotube (TNT) via spin-assisted layer-by-layer technique. The results of both Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance ( 1 H NMR) confirmed the successful synthesis of SL. The multilayer structure on BMP2 loaded TNT was characterized by field-emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and water contact angle, respectively. The release profiles confirmed that hyaluronidase could trigger the release of lauric acid (LA) from the SL multilayer and accelerate the release of BMP2 in the system. The hyaluronidase-sensitive-multilayer-coated BMP2-loaded TNT (TNT/BMP2/(Chi/SL/Chi/Gel) 4 ) not only demonstrated good antibacterial capability, but also showed good biocompatibility in in vitro usage, which was supported by the efficient growth inhibition of both Staphylococcus aureus and Escherichia coli , as well as higher cell viability, alkaline phosphatase activity, mineralization capability, and higher gene expression of osteoblasts on TNT/BMP2/(Chi/SL/Chi/Gel) 4 . This study developed an alternative approach to fabricate effective antibacterial implants for orthopedic implantation. [ABSTRACT FROM AUTHOR]

Organic-inorganic hybrid membranes represent an efficient approach to construct membranes with both improved membrane flux and solute selectivity. Zwitterions bearing equimolar number of anions and cations in one monomer unit exhibit excellent anti-fouling characteristics. Based on the exceptional separation performance of hybrid membrane and fouling resistance feature of zwitterions, a novel nanofiltration membrane was fabricated by incorporating zwitterionic functionalized titanium nanotubes (z-TNTs) into polyamide (PA) layer. The special tubular structure of z-TNTs can provide more and shorter internal channels to shorten flow lanes for water molecules. The zwitterionic functionalization on the titanium nanotubes surface improved not only the interfacial compatibility between nano-materials and polymer matrix but also the antifouling performance of membranes. The water flux of membrane prepared with z-TNTs was up to 220 L m−2 h−1 MPa−1 while the Na2SO4 rejection remained above 90%. The as-prepared z-TNTs/PA membrane exhibited improved anti-fouling property against protein with a notably reduced flux decline ratio. [ABSTRACT FROM AUTHOR]

The paper discusses the synthesis, photoelectrochemical and electrochemical behaviour of titania nanotube arrays modified by a pyrolyzed metal-organic framework (MOF). A poly(3,4–ethylenedioxyphene) (PEDOT) matrix with an embedded inorganic network of iron hexacyanoferrate (BP) covering TiO 2 nanotubes (TNT) is used as a MOF for the further sintering procedure, resulting in a novel, thin film of carbonaceous wrap supported Fe catalytic centers: TNT@C:Fe. UV–Vis and Raman spectroscopies were utilized to characterize the absorbance capability and the crystalline phase of titania, respectively. XPS was used for identification of the valence stage of iron Fe(0), Fe(II), Fe(III) in the shell part of the novel composite TNT@C:Fe. The electrochemical performance of the modified nanotubular TiO 2 electrodes has been monitored by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge cycles in an aqueous electrolyte. TNT@C:Fe exhibited the capacitance of 9.1 mF cm −2 even after 5000 cycles, being much higher than pure titania (2.1 mF cm −2 ). The photocurrent density reached 304 μA cm −2 for TNT@C:Fe, whereas only 32 μAcm −2 was registered for pure titania nanotubes under simulated solar light illumination at a potential of +0.5 V. An improved decolorization rate of methylene blue in water confirms enhanced photoactivity of TNT@C:Fe in comparison with pristine titania nanotubes. [ABSTRACT FROM AUTHOR]

In this study, an innovative carbon-free electrocatalyst for oxygen reduction reaction was synthesized via deposition of platinum on titanium nanotube suboxide (trititanium pentoxide nanotubes, TNTS) obtained from titania doped with molybdenum (Pt/TNTS-Mo). The TNTS-Mo support was synthesized in autoclave, while the Pt/TNTS-Mo using the polyol method. The carbon-free support and the Pt-based catalyst were fully characterized via rotating disk electrode (RDE) technique and polymer exchange membrane fuel cell (PEMFC) station by preparing a membrane electrode assembly (MEA) with Nafion ® 115, loaded with 0.35 mg Pt cm −2 of Pt/TNTS-Mo at the cathode, and 0.35 mg Pt cm −2 of commercial Pt/C (E-TEK) at the anode. In RDE experiments, the Pt/TNTS-Mo exhibited low overpotential and remarkable electroactivity toward oxygen reduction reaction (ORR: mass activity of 110.7 mA mg Pt −1 at 0.9 V vs SHE). Moreover, the Pt/TNTS-Mo demonstrated excellent stability. Tests in a 25 cm 2 single cell PEMFC resulted to maximum power density of 0.52 W cm −2 . [ABSTRACT FROM AUTHOR]

Tungsten-copper co-sensitized TiO 2 nanotube films on titanium substrate, used as photoanodes in photoelectrochemical (PEC) water splitting to produce hydrogen, have been synthesized via anodization and chemical bath deposition (CBD) methods. Field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were used to study the morphology and elemental composition of the synthetic samples. UV–Vis diffuse reflection spectroscopy (UV–Vis DRS) was sued to investigate the optical features of the samples. The impact of copper and tungsten ratio on the photocatalytic behavior of co-sensitized TiO 2 nanotube photoelectrodes in PEC water splitting has been investigated. High photocatalytic activity has been exhibited by the co-sensitized TiO 2 nanotube samples due to the synergistic effects of the copper and tungsten. Sample T4 had the highest photoelectrochemical activity compared with other samples. In addition, this sample exhibited outstanding photochemical stability even after four runs in the photocatalytic test. A simple method for the synthesis of high performance co-sensitized TiO 2 nanotube photocatalysts for application in solar energy conversion has thus been proposed in this work. The advantages of these new photoanodes for practical applications are low cost, ease of synthesis, high activity in visible light and excellent stability. [ABSTRACT FROM AUTHOR]

Highly ordered titania nanotubes (TNTs) were synthesised by an electrochemical anodization method for supercapacitor applications. However, the capacitive performance of the TNTs was relatively low and comparable to the conventional capacitor. Therefore, in order to improve the capacitive performance of the TNTs, a fast and facile electrochemical reduction method was applied to modify the TNTs (R-TNTs) by introducing oxygen vacancies into the lattice. X-ray photoelectron spectroscopy (XPS) data confirmed the presence of oxygen vacancies in the R-TNTs lattice upon the reduction of Ti4+ to Ti3+. Electrochemical reduction parameters such as applied voltage and reduction time were varied to optimize the best conditions for the modification process. The electrochemical performance of the samples was analyzed in a three-electrode configuration cell. The cyclic voltammogram recorded at 200 mV s−1 showed a perfect square-shaped voltammogram indicating the excellent electrochemical performance of R-TNTs prepared at 5 V for 30 s. The total area of the R-TNTs voltammogram was 3 times larger than the unmodified TNTs. A specific capacitance of 11.12 mF cm−2 at a current density of 20 μA cm−2 was obtained from constant current charge-discharge measurements, which was approximately 57 times higher than that of unmodified TNTs. R-TNTs also displayed outstanding cycle stability with 99% capacity retention after 1000 cycles. [ABSTRACT FROM AUTHOR]

Chromium dioxide (CrO nanoparticle arrays were fabricated on Ti nano-pit array templates by hydrothermal synthesis using CrO3 aqueous solution as precursor. The Ti nano-pit array template was obtained by stripping TiO2 nanotube array formed on the Ti foil. CrO2 nanoparticles are arranged in honeycomb pattern in a large area and their surface density reaches cm. The CrO2 nanoparticle arrays show typical magnetic behavior, and the easy axis is parallel to the plane of Ti nano-pit array template. The influence of the concentration of CrO3 aqueous solution on the CrO2 nanoparticle arrays is studied and the mechanism of the formation of the CrO2 nanoparticle arrays is briefly discussed. CrO2 nanoparticle array was successfully fabricated on Ti nano-pit array template under supercritical hydrothermal conditions. The Ti nano-pit array template was obtained by removing the TiO2 nanotube array from Ti foil. The concentration of CrO3 and the Ti nano-pit array template play key roles in the growth of CrO2 nanoparticle array. [ABSTRACT FROM AUTHOR]

To enhance the localized bone remodeling at titanium-based implants under osteoporotic conditions, TiO 2 nanotube arrays (TNT) were used as nanoreserviors for raloxifene (Ral) and then covered with the hybrid multilayered coating of chitosan and alendronate grafted hyaluronic acid (HA-Aln) via a spin-assisted layer-by-layer technique. The fabrication of this system (TNT/Ral/LBL-Aln) was characterized by field emission scanning electron microscopy (SEM), atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS), respectively. The release test showed that the composited multilayers onto Ral-loaded TiO 2 nanotube substrate (TNT/Ral) could prevent the burst release of Ral from TiO 2 nanotube arrays and maintain stable Ral concentration at the implant site even after 192 h. The TNT/Ral/LBL-Aln system demonstrated higher alkaline phosphatase (ALP) activity, mineralization capability in osteoblasts as well as lower tartrate-resistant acid phosphatase (TRAP) activity in osteoclasts compared to both bare TiO 2 nanotube and TNT/Ral substrate, respectively. Moreover, the in vivo tests of micro-CT, histological staining and push-out testing showed that TNT/Ral/LBL-Aln implant could efficiently enhance the formation of new bone around the implant and promote bone binding in osteoporotic rabbits. The study indicated the potential application of TNT/Ral/LBL-Aln system for bone remodeling under osteoporotic condition. [ABSTRACT FROM AUTHOR]

We have employed noise thermometry for investigations of thermal relaxation between the electrons and the substrate in nanowires patterned from 40-nm-thick titanium film on top of silicon wafers covered by a native oxide. By controlling the electronic temperature $$T_\mathrm{e}$$ by Joule heating at the base temperature of a dilution refrigerator, we probe the electron-phonon coupling and the thermal boundary resistance at temperatures $$T_\mathrm{e}= 0.5$$ -3 K. Using a regular $$T^5$$ -dependent electron-phonon coupling of clean metals and a $$T^4$$ -dependent interfacial heat flow, we deduce a small contribution for the direct energy transfer from the titanium electrons to the substrate phonons due to inelastic electron-boundary scattering. [ABSTRACT FROM AUTHOR]

To improve the bioactivity of titanium implants, a homogeneous layer of TiO 2 nanotubes with a diameter of approximately 110 nm was prepared by anodization. Gelatin was immobilized onto TiO 2 nanotubes through an intermediate layer of polydopamine. The surface characteristics of different substrates were evaluated using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM) and contact angle measurements, respectively. These results demonstrate that gelatin was successfully immobilized onto TiO 2 nanotubes. In vitro cell culture experiments including immunofluorescence staining, cell viability, alkaline phosphatase (ALP), mineralization and the expression of osteogenic genes including runt-related transcription factor 2 (Runx2), ALP, collagen type I (Col I), and osteopontin (OPN) confirm that cell spreading, proliferation and osteoblastic differentiation were improved when cells were seeded onto gelatin-immobilized TiO 2 nanotubes. This resulting material shows great promise as a future material in titanium implant applications. [ABSTRACT FROM AUTHOR]

A facile and efficient solution combustion method was developed and employed in the fabrication of novel mesoporous carbon nitride and titanium dioxide (C3N4–TiO2) nanocomposites as advanced photocatalysts for wastewater remediation. Urea was used as the precursor of C3N4, while titanium tetra-isopropoxide served as the source of titanium. Yellow nanocomposites were produced as compared to the formed white TiO2 and C3N4 nanomaterials. Transmission electron microscopic images and N2 adsorption/desorption analysis revealed that the fabricated nanocomposites possessed a mesoporous structure and much larger surface areas as compared to the individual constituents. X-ray photoelectron spectroscopic measurements and thermogravimetric analysis were utilized to determine the composition and thermal stability of the C3N4–TiO2 nanocomposites. Tauc plots derived from the UV-vis absorption spectra revealed that the formation of the C3N4–TiO2 nanocomposites significantly narrowed the band gap energy, leading to a high visible light response in contrast to the individual TiO2 (∼3.2 eV) and C3N4 (∼2.8 eV) samples. The optimal composition of the C3N4–TiO2 nanocomposites was determined, and the new nanocomposite developed in this study exhibited high visible light activity in the photochemical oxidation of Rhodamine B, as compared to the mechanically mixed C3N4 and TiO2 sample. This significant improvement in photocatalytic activity may be attributed to the synergistic effects of the red shift in absorption and the large surface area. [ABSTRACT FROM AUTHOR]

Herein, we proposed a simple method to measure the inner resistance of a photoelectrochemical (PEC) sensor. Three photoanodes, including TiO 2 nanotubes array (TiO 2 NTs), g-C 3 N 4 /TiO 2 NTs and Mn 3 (BTC) 2 /g-C 3 N 4 /TiO 2 NTs (BTC = 1,3,5-benzene- tricarboxylic acid), were chosen as the models. It was shown the change in inner resistance of the photoanode is the main factor for the photocurrent response in a PEC sensor. Under light excitation, the inner resistance of the photoanode is reduced remarkably, resulting in the increment in the photocurrent. The influence of the light intensity on the inner resistance is less than that on the photocurrent, due to the synchronous change in photovoltage. With increasing concentration of hole scavengers (e.g., H 2 O 2 , ascorbic acid), the steady inner resistances of the three photoanodes are decreased. In the PEC sensor with Mn 3 (BTC) 2 /g-C 3 N 4 /TiO 2 NTs, the Mn 3 (BTC) 2 layer is served as a size-exclusion filter to prevent the diffusion of molecules with size larger than the apertures in crystals, which improves the selectivity of the PEC sensor to smaller molecules (e.g., H 2 O 2 ). The catalytic effect of Mn 3 (BTC) 2 to H 2 O 2 enhances the PEC response sensitivity to H 2 O 2 . Under optimized conditions, the reciprocal of the averaged steady effective inner resistance of Mn 3 (BTC) 2 /g-C 3 N 4 /TiO 2 NTs is in a linear correlation with the logarithmic concentration of H 2 O 2 in the range of 0.003 to 10 μM with a limit of detection of 1 nM. This PEC sensor was applied for H 2 O 2 determination in exhaled breath condensate samples. [ABSTRACT FROM AUTHOR]