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This study compared the topography of different titanium surface structures (TiO2 nanotube and grain) with similar elemental compositions (TiO2 and fluorine [F]) on the Ti surface. High magnification indicated that the surfaces of the control and etching groups were similar to each other in a flat, smooth form. The group anodized for 1 h was observed with TiO2 nanotubes organized very neatly and regularly. In the group anodized for 30 min after etching, uneven wave and nanopore structures were observed. In addition, MTT assay showed that the F of the surface did not adversely affect cell viability, and the initial cell adhesion was increased in the 2.8% F‐incorporated TiO2 nanograin. At the edge of adherent cells, filopodia were observed in spreading form on the surfaces of the anodizing and two‐step processing groups, and they were observed in a branch shape in the control and etching groups. Moreover, cell adhesion molecule and osteogenesis marker expression was increased at the F‐incorporated TiO2 nanostructure. In addition, it was found that the expression of p‐extracellular signal‐regulated kinase (ERK) and p‐cAMP response element‐binding protein (CREB) increased in the TiO2 nanograin with the nanopore surface compared to the micro rough and nanotube surfaces relative to the osteogenic‐related gene expression patterns. As a result, this study confirmed that the topographic structure of the surface is more affected by osteogenic differentiation than the pore size and that differentiation by specific surface composition components is by CREB. Thus, the synergy effect of osteogenic differentiation was confirmed by the simultaneous activation of CREB/ERK.

Purpose This systematic review and meta-analysis aims to synthesize evidence relating to the effects of TiO2 nanotubes on osseointegration in animal models. Materials and methods The focused question was "Does the preparation of TiO2 nanotubes on the surface of implants enhance osseointegration?" Searches were performed for relevant manuscripts up to September 2019 using the PubMed, Embase, Scopus and Google Scholar databases with terms such as "TiO2 nanotubes" in combination with "osseointegration", "osteogenic", "osteogenesis", and "bone regeneration". The titles, abstracts and full texts of the manuscripts were reviewed in accordance with the eligibility criteria. The meta-analysis were then performed to analyze the effects of TiO2 nanotubes in bone-implant contact (BIC) and biomechanical tests. Results Fourteen manuscripts were included for the systematic review and meta-analysis. Eleven studies showed that the results of a histological analysis, micro-CT evaluation and biomechanical tests were significantly higher near TiO2 than titanium. The meta-analysis demonstrating similar results in the BIC and biomechanical tests were obtained. The selected studies also showed the preferable nanotube diameter (70, 80, or 100 nm) to enhance osseointegration in BIC and/or bone area (BA). Conclusion TiO2 nanotubes, especially those with large diameters, enhanced osseointegration near titanium implants. Compared to bare nanotubes, TiO2 nanotube composite coatings resulted in higher osteogenic ability.

Well-defined, monolithic TiO2 nanotube thin films havebeen used as model anode electrodes to study Na-ion storage in anatase TiO2. It is shown that anatase TiO2 nanotubes with wall thicknesses up t ...

A confined MnO2 catalyst with MnO2 nanoparticles entrapped in TiO2 nanotube was synthesized through vacuum-assisted impregnation method. Due to the confinement effect of TiO2 nanotube, the electron density distribution between the exterior and interior nanotube surface is modulated. As such, the confined MnO2 can facilitate the formation and migration of active oxygen species in the catalyst. The catalyst exhibits the enhanced activity in the catalytic combustion of butane, and the reaction temperature is significantly lowered. This result demonstrates that the confined MnO2 in TiO2 nanotube can serve as a cost-effective catalyst for the elimination of VOCs from the air.

Sub‐wavelength laser‐induced periodic surface structures (LIPSS) created by ultrashort pulsed laser irradiation on the surface of titanium are used for the first time to template the electrochemical growth of titanium dioxide nanotube arrays, creating a combined structure we term LIPSS‐Sticks. This is an example of a double self‐organized process, as both LIPSS formation and electrochemical anodization involve spontaneous generation of order from initially nonordered precursors. LIPSS‐Sticks have a 2× greater visible to near‐infrared light (400–1400 nm) collection efficiency compared with flat titanium dioxide due to the enhanced light scattering from grating‐like structures. The growth of nanostructures with time is modeled electrostatically to explain the features of a templated anodization process that differ from the usual anodization of flat surfaces. This new templated growth method using two complementary fabrication techniques is general and can also be applied to Cu, W, Fe, and Al oxide surfaces.

Over the past five years a number of different synthesis approaches has been reported to obtain so-called ‘black’ titania. One of the outstanding features of the material is that certain synthesis processes lead to the formation of an intrinsic co-catalytic center and thus enable noble-metal free photocatalytic H2-generation. In the present work, using TiO2 nanotube layers, we compare three common ‘blackening’ approaches, namely i) the original high-pressure hydrogenation (HPT-H2), ii) a classic high temperature reduction in Ar, and iii) an electrochemical (cathodic) reduction. We demonstrate that except for high pressure hydrogenation also cathodic reduction leads to an activation of TiO2 - that is, it exhibits noble-metal-free photocatalytic H2 generation. Moreover, we show that a combination of cathodic reduction/high pressure hydrogenation leads to a synergistic effect, that is, a significant enhancement of the combined co-catalytic activity.

Herein, we use a facile procedure to graft a thin graphitic C3N4 (g-C3N4) layer on aligned TiO2 nanotube arrays (TiNT) by a one-step chemical vapor deposition (CVD) approach. This provides a platform to enhance the visible-light response of TiO2 nanotubes for antimicrobial applications. The formed g-C3N4/TiNT binary nanocomposite exhibits excellent bactericidal efficiency against Escherichia coli (E. coli) as a visible-light activated antibacterial coating, without the use of additional bactericides.

The rapid development of globalization and industrialization has caused a series of environment problems due to the increased consumption of fossil energy sources. To address these concerns, water splitting for hydrogen production in the presence of a semiconductor photocatalyst is studied extensively as a potential method to provide clean and renewable hydrogen source. In article 1600152, Yuekun Lai and co‐workers review various methods to construct 1D TiO2 nanotubes, and modified strategies to enhance solar light harvesting and energy conversion efficiency. Furthermore, the mechanism and applications of photo/photoelectro‐catalytic water splitting are comprehensively discussed.

Bioinspired surfaces with special wettability have attracted a significant attention in recent years because of their potential applications for no loss liquid transfer, anti-icing, and self-cleaning. Herein, the realization of two extreme superhydrophobic states on 1H, 1H, 2H, 2H–perfluorooctyltriethoxysilane-modified TiO2 nanotube arrays (NTAs) is described by changing the structural characteristics of nanotubes while keeping the surface chemical composition constant. The water adhesive force is regulated in a wide range from ≈4.4 to ≈89.6 μN by the nanotubular diameter, length, density, and surface roughness. The cooperation effect between the negative pressures induced by the volume change of sealed air-pockets and the van der Waals' attraction at solid–liquid interface contributes to the water adhesion. The superhydrophobic TiO2 NTAs with a high adhesive force is used as a “mechanical hand” to transfer water microdroplets without any loss, and the one with extremely low adhesive force is utilized as a self-cleaning and anti-icing surface.

Tripropylamine (TPA) is a highly toxic and carcinogenic compound, therefore, TPA concentration in water must be monitored to protect health and the environment. In this paper, an electrochemiluminescent (ECL) sensor was fabricated by immobilising Ru(bpy)32+-modified CuO nanoparticles (NPs) on a TiO2 nanotube array (TN) electrode. Compared to an ECL sensor fabricated by immobilising Ru(bpy)32+ on a TN only electrode, the as-prepared sensor displays a 30 % enhanced ECL signal and a detection limit of 9.6×10−10 M at a signal-to-noise ratio=3 with the concentration of TPA in a range 1×10−9 to 1×10−5 M. The results from this study indicated a new approach for the enhancement of performance of ECL sensor in detecting TPA in water.

A simple, rapid and environmental friendly online chemical oxygen demand (COD) analytical method based on TiO2 nanotube sensor in conjunction with the flow injection technique was proposed to determine the COD of aqueous samples, especially for refractory organics, low-concentration wastewater, and surface water. The new method can overcome the drawbacks of the conventional COD determination methods. The results show that with the new method, each analysis takes only about 1 to 3 min, the linear range is up to 1 to 500 mg x L(-1) of the compound of interest, and the detection limit is 1 mg x L(-1). The COD values obtained by the proposed method are more accurate than those obtained by the conventional method.

Herein is described a facile, in situ, ink-regulating approach to rapidly achieve reversible water wettability and adhesion transition, with a large degree of contrast, on superhydrophobic TiO2 nanotube array film. The ink printing and removal process allows the wettability and reversible adhesion transitions to be realized. Experimental results demonstrate the potential application of such site-selective, sticky superhydrophobic patterns for droplet manipulation by in situ surface modification.

Recombination dynamics: For TiO(2) nanotube-based dye-sensitized solar cells, the efficiency can be drastically enhanced by a synergetic effect that occurs when using nanowire-ended nanotubes in combination with an adequate nanoparticle decoration (see figure).

Self-organized, freestanding TiO2 nanotube arrays that exhibit tube-in-tube morphology are fabricated using a one-step anodic method. These arrays are uniform and compact. The tubes within the arrays are several micrometers long with a 200 nm outer diameter. They have a coarse lateral profile that leads to a large aspect ratio and guarantees good photocatalytic properties.

National Nature Science Foundation of China [20773100, 20620130427]; MOST [2007DFC40440]; National Basic Research Program of China [2007CB935603]

Highly ordered TiO 2 nanotube arrays (TiO 2 -NTAs) are produced by electrochemical anodization of a Ti foil in ammonium fluoride (NH 4 F)-ethylene glycol solution. Photocatalytic (PC) investigations indicate that the length of the NTAs plays an important role in their photoactivity. The PC activity increases initially with the NT length and then decreases and the optimum length that yields the highest PC is 6.2 μm for TiO 2 -NTAs. The TiO 2 -NTAs are further converted to heterojunction strontium titanate (SrTiO 3 )/TiO 2 -NTAs by a hydrothermal reaction in Sr(OH) 2 solution. As the hydrothermal reaction proceeds, more TiO 2 is converted into SrTi0 3 and the thickness of the SrTi0 3 layer increases. The SrTiO 3 /TiO 2 -NTAs exhibit variable PC activities that depend on the hydrothermal reaction time, and the SrTiO 3 /TiO 2 -NTAs hydrothermally treated for 1 h or less have enhanced PC properties. The advantage of combining Ti0 2 and SrTi0 3 stems from the difference in the flatband potential, thereby improving the separation of the photogenerated electron-hole pairs and consequently the PC activity.

Two-layer TiO2 nanotube arrays were produced by stepping down the anodic voltage during which three nanotube interface structures between the top layer and the second layer were observed by SEM. We detected a polygonal ring structure on the top surface of the second layer and offer direct evidence of the growth of this second tube layer both at the cell boundary and right beneath the bottom of the first tube layer. For these processes, a possible growth mechanism is presented. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Gradient TiO2 nanotube arrays were fabricated by anodization using an asymmetric electrode configuration. The nanotube arrays thus obtained display a gradually changing distribution of tube diameters and length across the sample plane. The application of the fabricated gradient TiO2 nanotube arrays as optical sensors is also demonstrated. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)