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Polyaniline/carbon doped TiO2 composite nanotube arrays (PANI/C-TiO2 NTAs) have been prepared successfully by electrodepositing PANI in C-TiO2 NTAs which were prepared by directly annealing the as-anodized TiO2 NTAs under Ar atmosphere. The organic residual in the TiO2 NTAs during the process of anodization acts as carbon source and is carbonized in Ar atmosphere to manufacture the C-TiO2 NTAs. The specific capacitance of the PANI/C-TiO2 electrode is 120.8 mF cm−2 at a current density of 0.1 mA cm−2 and remains 104.3 mF cm−2 at a current density of 2 mA cm−2 with the calculated rate performance of 86.3%. After 5000 times of charge-discharge cycling at a current density of 0.2 mA cm−2, the specific capacitance retains 88.7% compared to the first cycle. All these outstanding performances of the as-prepared PANI/C-TiO2 NTAs indicate it will be a promising electrode for supercapacitor. [ABSTRACT FROM AUTHOR]

Porous dual-layered molybdenum oxide (MoO x) nanotube arrays (NTAs) with highly conductive titanium nitride (TiN) cores (MoO x/TiN/MoO x NTAs) are fabricated by depositing MoO x on porous TiN NTAs produced by nitriding as-anodized TiO2 NTAs on Ti foils. The highly conductive TiN facilitates electron transfer and the porous MoO x wall allows the electrolyte to permeate the nanotubes readily, maximizing the active sites of the MoO x electroactive material to improve the specific capacitance and rate capability. The coaxial MoO x/TiN/MoO x NTA electrode shows a high specific capacitance of 97 mF cm−2 (323 F g−1) at a current density of 1 mA cm−2, and 60 % capacitance is retained when the current density is increased 20 times. A symmetrical device based on the MoO x/TiN/MoO x NTA electrode exhibits a capacitance as high as 24 F cm−3 (based on the volume of MoO x/TiN/MoO x NTAs) and no significant decay is observed after charging/discharging for 10 000 cycles. [ABSTRACT FROM AUTHOR]

Poor osseointegration and infection resulting from implants are serious medical issues, and it is not straightforward to manufacture implants that can simultaneously address both of these problems. In this study, we produced coatings containing titania nanotubes (TiO2-NTs) incorporated with zinc (NT-Zn) on Ti substrates by anodization and hydrothermal treatment. The zinc content was controlled by varying the duration of the hydrothermal treatment. The NT-Zn implants not only exhibited improved bone formation (shown by both in vitro and in vivo studies), which enhances osseointegration between bone and implant, but also inhibited growth of bacteria. The cytotoxicity of locally high concentrations of zinc in the NT-Zn3h specimens observed during in vitro studies was mitigated by the effects of dilution in vivo. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 3939-3950, 2014. [ABSTRACT FROM AUTHOR]

Antibiotic-resistant bacteria have become a major issue due to the long-term use and abuse of antibiotics in treatments in clinics. The combination therapy of antibiotics and silver (Ag) nanoparticles is an effective way of both enhancing the antibacterial effect and decreasing the usage of antibiotics. Although the method has been proved to be effective in vitro, no in vivo tests have been carried out at present. Herein, we described a combination therapy of local delivery of Ag and systemic antibiotics treatment in vitro in an infection model of rat. Ag nanoparticle-loaded TiO2 nanotube (NT) arrays (Ag-NTs) were fabricated on titanium implants for a customized release of Ag ion. The antibacterial properties of silver combined with antibiotics vancomycin, rifampin, gentamicin, and levofloxacin, respectively, were tested in vitro by minimum inhibitory concentration (MIC) assay, disk diffusion assay, and antibiofilm formation test. Enhanced antibacterial activity of combination therapy was observed for all the chosen bacterial strains, including gram-negative Escherichia coli (ATCC 25922), gram-positive Staphylococcus aureus (ATCC 25923), and methicillin-resistant Staphylococcus aureus (MRSA; ATCC 33591 and ATCC 43300). Moreover, after a relative short (3 weeks) combinational treatment, animal experiments in vivo further proved the synergistic antibacterial effect by X-ray and histological and immunohistochemical analyses. These results demonstrated that the combination of Ag nanoparticles and antibiotics significantly enhanced the antibacterial effect both in vitro and in vivo through the synergistic effect. The strategy is promising for clinical application to reduce the usage of antibiotics and shorten the administration time of implant-associated infection.

• The ultrathin carbon layer coated TiN (TiN/C) is in situ fabricated. • The protection by carbon layer can mitigate the electrochemical oxidation of TiN. • The TiN/C exhibits a large volumetric capacitance of 121 F cm−3, much larger than pure TiN (69 F cm−3) Although titanium nitride (TiN) is promising as electrode material in supercapacitors due to the high conductivity, there are drawbacks such as the brittleness, low capacitance, and chemical stability. Herein, three-dimensional (3D) carbon-encapsulated mesoporous titanium nitride nanotubes (TiN/C NTs) arrays with carbon doping are prepared by one-step nitridation of anodic TiO 2 NTs with organic electrolyte as the carbon source. In TiN/C NTs, 3D carbon matrix not only serves as a protective layer and mechanical support to mitigate electrochemical oxidation and structural collapse, but also provides a conductive network to facilitate electron transfer. The capacitance retention of the TiN NTs electrodes increases from 72.5 to 92.2% for 4000 cycles after carbon encapsulating. Moreover, the carbon doping increases the active charge storage sites of the TiN NTs. The TiN/C NTs electrode exhibits a large volumetric capacitance of 121 F cm−3 (0.83 A cm−3), which is one time larger than that of the pure TiN NTs (69 F cm−3). The symmetrical all-solid-state device assembled with two TiN/C NTs electrodes and polyvinyl alcohol electrolyte shows a large volumetric capacitance of 8.3 F cm−3. This finding provides a good potential application in flexible supercapacitor. [ABSTRACT FROM AUTHOR]

Implants made of Ti and its alloys are widely utilized in orthopaedic surgeries. However, insufficient osseointegration of the implants often causes complications such as aseptic loosening. Our previous research discovered that disordered titanium dioxide nanorods (TNrs) had satisfactory antibacterial properties and biocompatibility, but TNrs harmed angiogenic differentiation, which might retarded the osseointegration process of the implants. Magnetic nanomaterials have a certain potential in promoting osseointegration, electromagnetic fields within a specific frequency and intensity range can facilitate angiogenic and osteogenic differentiation. Therefore, this study used Fe 3 O 4 to endow magnetism to TNrs and explored the regulation effects of Ti, TNrs, and Fe 3 O 4 -TNrs under 1 ​mT 15 ​Hz sinusoidal electromagnetic field (SEMF) on osteoblastogenesis, osseointegration, angiogenesis, and its mechanism. We discovered that after the addition of SEMF treatment to VR-EPCs cultured on Fe 3 O 4 -TNrs, the calcineurin/NFAT signaling pathway was activated, which then reversed the inhibitory effect of Fe 3 O 4 -TNrs on angiogenesis. Besides, Fe 3 O 4 -TNrs with SEMF enhanced osteogenic differentiation and osseointegration. Therefore, the implant modification mode of Fe 3 O 4 -TNrs with the addition of SEMF could more comprehensively promote osseointegration and provided a new idea for the modification of implants., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Although titanium and its alloys are widely used in bone surgeries, the implantation failures caused by sterile inflammation still occur. The excessive reactive oxygen species (ROS) in the peri-implant region are considered to cause inflammation and impede the osseointegration of titanium implants. In this study, a coating of resveratrol-loaded titania nanotube (TNT-Res) for eliminating ROS was fabricated on titanium surface through electrochemical anodization and following surface adsorption of resveratrol. The resveratrol concentration of released from TNT-Res coating was controlled by modulating the loading amount. The ROS production in macrophage cell lineage RAW 264.7 and bone mesenchymal stem cells (BMSCs) were significantly decreased when cultured on TNT-Res coatings. The pro-inflammatory factors, including tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β), and NO produced by RAW 264.7 cells were reduced when cells were cultured on TNT-Res coatings. These results proved that the TNT-Res coating can effectively eliminate ROS and inhibit inflammation. Moreover, the osteogenic indicators, including alkaline phosphatase (ALP) production, extracellular calcium deposition, and osteogenesis-related gene expression, including collagen І (Col-І), osteocalcin (OCN), osteopontin (OPN), and runt-related transcription factor 2 (Runx2), were significantly promoted for TNT-Res groups, which demonstrated that the TNT-Res coating can enhance the osteogenic differentiation of BMSCs. Additionally, the phosphorylation of nuclear factor κ-B (NF-κB) were down-regulated both in RAW 264.7 cells and BMSCs, which indicated that the TNT-Res coating could inhibit inflammation and promote osteogenesis by inhibiting the activation of NF-κB signaling pathway. The TNT-Res coating could be an effective implant surface for improving osseointegration ability of titanium implants., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Introduction: The bone regeneration of endosseous implanted biomaterials is often impaired by the host immune response, especially macrophage-related inflammation which plays an important role in the bone healing process. Thus, it is a promising strategy to design an osteo-immunomodulatory biomaterial to take advantage of the macrophage-related immune response and improve the osseointegration performance of the implant., Methods: In this study, we developed an antibacterial silver nanoparticle-loaded TiO 2 nanotubes (Ag@TiO 2 -NTs) using an electrochemical anodization method to make the surface modification and investigated the influences of Ag@TiO 2 -NTs on the macrophage polarization, osteo-immune microenvironment as well as its potential molecular mechanisms in vitro and in vivo., Results: The results showed that Ag@TiO 2 -NTs with controlled releasing of ultra-low-dose Ag + ions had the excellent ability to induce the macrophage polarization towards the M2 phenotype and create a suitable osteo-immune microenvironment in vitro, via inhibiting PI3K/Akt, suppressing the downstream effector GLUT1, and activating autophagy. Moreover, Ag@TiO 2 -NTs surface could improve bone formation, suppress inflammation, and promote osteo-immune microenvironment compared to the TiO 2 -NTs and polished Ti surfaces in vivo. These findings suggested that Ag@TiO 2 -NTs with controlled releasing of ultra-low-dose Ag + ions could not only inhibit the inflammation process but also promote the bone healing by inducing healing-associated M2 polarization., Discussion: Using this surface modification strategy to modulate the macrophage-related immune response, rather than prevent the host response, maybe a promising strategy for implant surgeries in the future., Competing Interests: The authors have declared that no competing interest exists and that they have no conflicts of interest in this work., (© 2020 Chen et al.)

Background: Titanium (Ti) implant-associated infection, which is mostly caused by bacterial adhesion and biofilm formation, may result in implant failure and secondary surgery. Thus it is an urgent issue to prevent bacterial infections at the earliest step. Purpose: To develop a novel surface strategy of polydopamine (PDA) and silver (Ag) nanoparticle-loaded TiO 2 nanorods (NRDs) coatings on Ti alloy. Materials and methods: Ag-TiO 2 @PDA NRDs was fabricated on Ti alloy by hydrothermal synthesis. The antibacterial activity of Ag-TiO 2 @PDA NRDs against Escherichia coli and methicillin-resistant Staphylococcus aureus were tested by FE-SEM, Live/Dead staining, zone of inhibition, bacteria counting method and protein leakage analysis in vitro . In addition, an implant infection model was conducted and the samples were tested by X-ray, Micro-CT and histological analysis in vivo . Besides, cell morphology and cytotoxicity of Mouse calvarial cells (MC3T3-E1) were characterized by FE-SEM, immunofluorescence and CCK-8 test in vitro . Results: Our study successfully developed a new surface coating of Ag-TiO 2 @PDA NRDs. The selective physical puncture of bacteria and controlled release of Ag+ ions of Ag-TiO 2 @PDA NRDs achieved a long-lasting bactericidal ability and anti-biofilm activity with satisfied biocompatibility. Conclusion: This strategy may be promising for clinical applications to reduce the occurrence of infection in the implant surgeries., Competing Interests: There are no potential conflicts of interest for the authors to disclose in this work.

Efficient and stable non-precious metal based electrocatalysts are crucial to the hydrogen evolution reaction (HER) in renewable energy conversion. Herein, Co x P nanoparticles (NPs) are uniformly embedded in N-doped TiO 2 nanotube arrays (Co x P/N-TiO 2 NTAs) by low-temperature phosphorization of the precursor of metallic cobalt NPs embedded in N-doped TiO 2 NTAs (Co/N-TiO 2 NTAs) which were fabricated by phase separation of CoTiO 3 NTAs in ammonia. Owing to the abundant exposed surface active sites of Co x P NPs, tight contact between the Co x P NPs and TiO 2 NTAs, fast electron transfer in N-doped TiO 2 , and channels for effective diffusion of ions and H 2 bubbles in the tubular structure, the Co x P/N-TiO 2 NTAs have excellent electrocatalytic activity in HER exemplified by a low overpotential of 180 mV at 10 mA cm -2 and small Tafel slope of 51 mV dec -1 in 0.5 M H 2 SO 4 . The catalyst also shows long-term cycling stability and is a promising non-precious metal catalyst for HER., Competing Interests: The authors declare no conflicts of interest., (This journal is © The Royal Society of Chemistry.)

Aim: To create polydopamine (PDA) and Ag nanoparticle-loaded TiO 2 nanotubes coating on titanium (Ti) alloy., Materials & Methods: TiO 2 -PDA-Ag coating was fabricated on Ti implants by electrochemical anodization. The in vitro and in vivo bactericidal and antibiofilm activities were tested. Intracellular reactive oxygen species (ROS) and antioxidative capability were measured, and cell proliferation, adhesion and cell morphology were characterized., Results: TiO 2 -PDA-Ag coating showed satisfactory bactericidal and antibiofilm activities in vitro and in vivo, improved Ag release pattern, evident ROS scavenging properties and enhanced cell adhesion and proliferation., Conclusion: Our study successfully fabricated a PDA and Ag nanoparticle-loaded TiO 2 nanotubes coating on Ti alloy. The improved Ag release kinetics and ROS-scavenging properties achieve an optimal balance between antibacterial ability and biocompatibility.

Molybdenum phosphide (MoP) is a promising non-noble-metal electrocatalyst in the hydrogen evolution reaction (HER), but practical implementation is impeded by the sluggish HER kinetics and poor chemical stability. Herein, a novel high-efficiency HER electrocatalyst comprising MoP nanoflakes intercalated nitrogen-doped graphene nanobelts (MoP/NG), which are synthesized by one-step thermal phosphiding organic-inorganic hybrid dodecylamine (DDA) inserted MoO 3 nanobelts, is reported. The intercalated DDA molecules are in situ carbonized into the NG layer and the sandwiched MoO 3 layer is converted into MoP nanoflakes which are intercalated between the NG layers forming the alternatingly stacked MoP/NG hybrid nanobelts. The MoP nanoflakes provide abundant edge sites and the sandwiched MoP/NG hybrid enables rapid ion/electron transport thus yielding excellent electrochemical activity and stability for HER. The MoP/NG shows a low overpotential of 94 mV at 10 mA cm -2 , small Tafel slope of 50.1 mV dec -1 , and excellent electrochemical stability with 99.5% retention for over 22 h., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Flexible supercapacitors (SCs) are desirable for elastic and clothing electronic products owning to their considerable safety, high foldability and outstanding power density. Herein, multilayered films composed of alternating mesoporous Nb4N5 nanobelts and rGO nanosheets (Nb4N5/rGO) are designed and fabricated exhibiting good flexibility. The folding Nb4N5/rGO film electrode reveals an areal capacitance of 141 mF cm-2 (at 1 mA cm-2) along with remarkable cycling stability (the capacitance retention is 90% after 6,000 cycles). The flexible SCs devices were constructed by interlayer couple films of Nb4N5/rGO electrodes with PVA/H2SO4 gel as the electrolyte, which exhibited huge volumetric capacitance of 19 F cm-3 (at 0.1 A cm-3) and a considerable energy density of 0.98 mW h cm-3 with a power density of 0.029 W cm-3. Additionally, the as-obtained folding devices bode outstanding cycling stability with capacitance retention of 89% after 4,000 cycles measured by cyclic voltammetry method (at 100 mV s-1). Above results about niobium nitride based flexible electrodes and devices exploit a platform for wearable electronics and flexible devices.

A novel and simple strategy for the in situ fabrication of the microstructure composed of nickel (Ni) nanoparticles on nitrogen-doped TiO 2 nanowire arrays (Ni NPs/TiO x N y NWAs) by nitridation of NiTiO 3 nanowire arrays is designed and described. During nitridation, Ni is separated from NiTiO 3 and aggregates uniformly on the surface. The reshaped composite that is supported by the compact structure and interface of the formed NPs and remaining highly conductive TiO x N y NW forms a robust electrode in highly sensitive and selective non-enzymatic glucose sensing. The materials exhibit outstanding electrocatalytic activity for glucose oxidation boasting a sensitivity of 421 μA mM -1 cm -2 , a low detection limit of 0.39 μM, as well as high selectivity against interfering species such as ascorbic acid (AA), uric acid (UA) and dopamine (DA).

Quasi-aligned cylindrical and conical core-shell nanofibers consisting of carbon shells and TiO(2) nanowire cores are produced in situ on Ti foils without using a foreign metallic catalyst and template. A cylindrical nanofiber has a TiO(2) nanowire core 30-50 nm in diameter and a 5-10 nm-thick cylindrical carbon shell, while in the conical nanostructure the TiO(2) nanowire core has a diameter of 20-40 nm and the thickness of the carbon shell varies from about 200 nm at the bottom to about 5 nm at the tip. Electrochemical analysis reveals well-defined redox peaks of the [Fe(CN)(6)](3-/4-) redox couple and heterogeneous charge-transfer rate constants of 0.010 and 0.062 cm  s(-1) for the cylindrical and conical nanofibers, respectively. The coverage of exposed edge planes on the cylindrical and conical carbon shells is estimated to be 2.5 and 15.5 % respectively. The more abundant exposed edge planes on the conical nanofiber decrease the overpotential and increase the voltammetric resolution during electrochemical detection of uric acid and ascorbic acid. Our results suggest that the density of edge-plane sites estimated from Raman scattering is not necessarily equal to the density of exposed edge-plane sites, and only carbon electrodes with a large density of exposed edge planes or free graphene sheet ends exhibit better electrochemical performance., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The vapor-liquid-solid (VLS) growth model has been widely used to direct the growth of one-dimensional (1D) nanomaterials, but the origin of the proposed process has not been experimentally confirmed. Here we report the experimental evidence of the origin of VLS growth. Al(69)Ni(31) alloyed particles are used as "catalysts" for growing AlN nanowires by nitridation reaction in N(2)-NH(3) at different temperatures. The nanowire growth occurs following the emergence of the catalyst droplets as revealed by in situ X-ray diffraction and thermal analysis. The physicochemical process involved has been elucidated by quantitative analysis on the evolution of the lattice parameters and relative contents of the nitridation products. These direct experimental results reveal that VLS growth of AlN nanowires is dominated by the phase equilibrium of the Al-Ni alloy catalyst. The in-depth insight into the VLS mechanism indicates the general validity of this growth model and may facilitate the rational design and controllable growth of 1D nanomaterials according to the corresponding phase diagrams.

A simple chemical method for the production of single-crystalline alpha-Si(3)N(4) nanobelts has been developed, consisting of nitridation of a high-Si-content Fe-Si 'catalyst' by ammonia at 1300 degrees C. The as-synthesized product was characterized by means of x-ray diffraction, electron microscopy and energy-dispersive x-ray spectroscopy. The alpha-Si(3)N(4) nanobelts have widths of 60-120 nm, thicknesses of 10-30 nm and lengths up to microns. Four intense green-blue luminescence bands at 398 nm (3.12 eV), 434 nm (2.86 eV), 492 nm (2.52 eV) and 540 nm (2.30 eV) were observed and analysed for the product, which indicates the potential applications in optoelectronics. The growth mechanism has also been speculated upon. The potential technological importance of the product, the simplicity of the preparation procedure, as well as the cheap commercial precursor of Fe-Si alloy particles makes this study both scientifically and technologically interesting.