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Blood coagulation and inflammation are the earliest biological responses to implant surfaces. Implant nano-surfaces can significantly impact the osseointegration through the influence on the early phase of bone regeneration. However, the interplay between blood clot property and inflammatory reaction on nanosurfaces is rarely understood. Herein, titania nanotube arrays (TNAs) with different diameters are fabricated on titanium. In vitro evaluation with the whole blood indicates that TNA with a diameter of 15 nm (TNA 15) enables noteworthy platelet activation resulting in distinct clot features compared with that of pure Ti and TNA with a diameter of 120 nm (TNA 120). Further co-culture with macrophages on the clot or in the clot-conditioned medium shows that the clot on TNA 15 downregulates the inflammation and manipulates a favorable osteoimmunomodulatory environment for osteogenesis. In vivo studies further demonstrate that TNA 15 could downregulate the inflammation-related genes while upregulating growth metabolism-related genes in an early healing hematoma. Additionally, TNA 15 promotes de novo bone formation with improved extending of osteocyte dendrites, demonstrating the desired osseointegration. These findings indicate that surface nano-dimensions can significantly influence clot formation and appropriate clot features can manipulate a favorable osteoimmunomodulatory environment for bone regeneration and osseointegration., (© 2020 Wiley-VCH GmbH.)

Prevention of bacterial infection and promotion of osseointegration are two important issues for titanium (Ti) implants in medical research. In addition, after a biofilm is formed on the surface of implants, the immune system and antibiotic therapy may fail. In this work, bio-functionalized titanium dioxide (TiO 2 )/molybdenum disulfide (MoS 2 )/polydopamine (PDA)/arginine-glycine-aspartic acid (RGD) nanorod arrays (NAs) are prepared on Ti implants to not only kill bacteria noninvasively upon co-irradiation of 660 nm visible light (VL) and 808 nm near infrared (NIR) light, but also promote the osteogenic activity simultaneously. Dual light irradiation triggers the TiO 2 /MoS 2 NA to generate hyperthermia and reactive oxygen species (ROS) in 10 min. The synergistic effects of the generated hyperthermia and ROS increase the bacterial membrane permeability and bacteria are killed rapidly and efficiently in vitro and in vivo. The biofilm is also eradicated and RGD on the nanorods improves cell adhesion, proliferation, and osteogenic differentiation. The strategy described here for the design of bio-functionalized coatings on Ti implants has great clinical potential in orthopedics, dentistry, and other medical fields.

Inflammatory reactions and the functionality of endothelial cells (ECs) on the surfaces of coronary stents are critical in the prevention of in-stent restenosis and subsequent neoatherosclerosis. However, the interactions between immune cells and ECs on modified coronary stent surfaces have long been underestimated. In the present study, silicon (Si)-doped titania nanotube arrays (TNA-Sis) were obtained via the facile anodization of magnetron-sputtered Ti-Si coatings. The synergetic effects of titania nanotube arrays (TNAs) and chemical cues (Si) on the functionality of macrophages (MΦs)/ECs and their cross-talk were investigated. The results indicated that TNA-Sis specimens, in comparison with TNAs alone, not only promoted the initial vitality of ECs, enhanced the expression of vascular endothelial growth factor (VEGF) and nitric oxide (NO), and activated multiple cell signaling pathways (vWF, PECAM, eNOS), but also induced a favorable immune response through the polarization of MΦs to a pro-healing M2 phenotype via the activation of cell autophagy, resulting in the downregulation of inflammatory reactions. This beneficial immune response further facilitated cross-talk between ECs and MΦs, resulting in profoundly increased functionality of ECs on TNA-Sis surfaces. This study demonstrated that using TNA-Sis surface coatings for coronary stents may be a promising strategy to prevent in-stent restenosis.

Coating materials applied for intraosseous implants must be optimized to stimulate osseointegration. Osseointegration is a temporal and spatial physiological process that not only requires interactions between osteogenesis and angiogenesis but also necessitates a favorable immune microenvironment. It is now well-documented that hierarchical nano-micro surface structures promote the long-term stability of implants, the interactions between nano-micro structure and the immune response are largely unknown. Here, we report the effects of microporous titanium (Ti) surfaces coated with nano-hydroxyapatite (HA) produced by micro-arc oxidation and steam-hydrothermal treatment (SHT) on multiple cell behavior and osseointegration. By altering the processing time of SHT it was possible to shift HA structures from nano-particles to nano-rods on the microporous Ti surfaces. Ti surfaces coated with HA nano-particles were found to modulate the inflammatory response resulting in an osteoimmune microenvironment more favorable for osteo-/angio-genesis, most likely via the activation of certain key signaling pathways (TGF-β, OPG/RANKL, and VEGF). By contrast, Ti surfaces coated with nano-rod shaped HA particles had a negative impact on osteo-/angio-genesis and osteoimmunomodulation. In vivo results further demonstrated that Ti implant surfaces decorated with HA nano-particles can stimulate new bone formation and osseointegration with enhanced interaction between osteocytes and implant surfaces. This study demonstrated that Ti implants with micro-surfaces coated with nano-particle shaped HA have a positive impact on osseointegration., Statement of Significance: Osteo-/angio-genesis are of importance during osteointegration of the implants. Recent advances unravel that immune response of macrophages and its manipulated osteoimmunomodulation also exerts a pivotal role to determine the fate of the implant. Surface nano-micro modification has evidenced to be efficient to influence osteogenesis, however, little is known links nano-microstructured surface to immune response, as well the osteoimmunomodulation. This study demonstrates that the nano-particles decorated micro-surface, compared with the nano-rods decorated micro-surface enables osteogenesis and angiogenesis concurrently that has not been investigated previously. This study also unravels that the immune response of macrophages can be manipulated by the nano-micro surface, especially the nano-dimension matters, leading to a differential effect on osteointegration. The additional knowledge obtained from this study may provide foundation and reference for future design of the coating materials for implantable materials., (Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Bacterial infection and loosening of orthopedic implants remain two disastrously postoperative complications. Angiogenesis is critical important to facilitate implant osseointegration in vivo. TiO 2 nanotubes arrays (NTAs) with proper dimensions possess good osseointegration ability. Accordingly, the present work incorporated copper (Cu) into TiO 2 NTAs (Cu-Ti-O NTAs) to enhance their antibacterial ability and angiogenesis activity, which was realized through anodizing magnetron-sputtered TiCu coatings with different Cu contents on pure titanium (Ti). Our results show ordered Cu-Ti-O NTAs can be produced under proper Cu content (<15.14%) in TiCu coatings. The NTAs possess excellent long-term antibacterial ability against Staphylococcus aureus (S. aureus), which may be ascribed to sustained release of Cu 2+ . The cytotoxicity of Cu-Ti-O NTAs to endothelial cells (ECs) could be negligible and can even promote cell proliferation as revealed by live/dead staining and MTT. Meanwhile, Cu-Ti-O NTAs can up-regulate nitric oxide (NO) synthesis and vascular endothelial growth factors (VEGF) secretion of ECs on the sample surfaces compared with that of pure TiO 2 NTAs (control). Furthermore, the angiogenic activity is also enhanced in ionic extracts of Cu-Ti-O NTAs compared with the control. The excellent long-term antibacterial ability and favorable angiogenic activity render Cu-Ti-O NTAs to be promising implant coatings., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Anodization is used to fabricate Ni-Ti-O nanotube (NT) electrodes for non-enzymatic glucose detection. The morphology, microstructure and composition of the materials are characterized by field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). Our results show amorphous and highly ordered NTs with diameter of 50nm, length of 800nm, and Ni/Ti ratio (at %) of 0.35 can be fabricated in ethylene glycol electrolyte supplemented with 0.2 wt.% NH4F and 0.5 vol.% H2O at 30°C and 25V for 1h. Electrochemical experiments indicate that at an applied potential of 0.60V vs. Ag/AgCl, the electrode exhibits a linear response window for glucose concentrations from 0.002mM to 0.2mM with a response time of 10s, detection limit of 0.13μM (S/N=3), and sensitivity of 83μAmM(-1)cm(-2). The excellent performance of the electrode is attributed to its large specific area and fast electron transfer between the NT walls. The good electrochemical performance of the Ni-Ti-O NTs as well as their simple and low-cost preparation method make the strategy promising in non-enzymatic glucose detection., (Copyright © 2015. Published by Elsevier B.V.)

TiO2 nanotubes (NTs) have favorable biological properties, but the poor antibacterial activity limits their application especially in orthopedics fields. In this article, Cu-Ti-O nanotubes with different Cu contents are fabricated on sputtered TiCu films. Scanning electron microscopy reveals the NTs can be formed on sputtered TiCu films when the Cu content is less than 14.6 at %. X-ray photoelectron spectroscopy results indicate the NTs are consist of CuO mixed with TiO2 and the Cu content in NTs decreases dramatically compared with that in TiCu films. Biological experiments show that although these NTs have poor release antibacterial activity, their contact antibacterial activity has proven to be excellent, indicating the NT surface can effectively inhibit biomaterial-associated infections. The cytocompatibility of the NTs is closely related to the Cu content and when its content is relatively low (1.01 at %), there is no appreciable cytotoxicity. So Cu-Ti-O NTs with 1 at % Cu may be suitable to achieve proper antibacterial activity and desired cytocompatibility. The Cu-Ti-O NTs integrate the favorable antibacterial activity of Cu and excellent biological properties of TiO2 NTs therefore have potential applications in orthopedics, dentistry, and other biomedical fields., (Copyright © 2013 Society of Plastics Engineers.)

A versatile strategy to endow biomaterials with long-term antibacterial ability without compromising the cytocompatibility is highly desirable to combat biomaterial related infection. TiO2 nanotube (NT) arrays can significantly enhance the functions of many cell types including osteoblasts thus having promising applications in orthopedics, orthodontics, as well as other biomedical fields. In this study, TiO2 NT arrays with Ag2O nanoparticle embedded in the nanotube wall (NT-Ag2O arrays) are prepared on titanium (Ti) by TiAg magnetron sputtering and anodization. Well-defined NT arrays containing Ag concentrations in a wide range from 0 to 15 at % are formed. Ag incorporation has little influence on the NT diameter, but significantly decreases the tube length. Crystallized Ag2O nanoparticles with diameters ranging from 5 nm to 20 nm are embedded in the amorphous TiO2 nanotube wall and this unique structure leads to controlled release of Ag(+) that generates adequate antibacterial activity without showing cytotoxicity. The NT-Ag2O arrays can effectively kill Escherichia coli and Staphylococcus aureus even after immersion for 28 days, demonstrating the long lasting antibacterial ability. Furthermore, the NT-Ag2O arrays have no appreciable influence on the osteoblast viability, proliferation, and differentiation compared to the Ag free TiO2 NT arrays. Ag incorporation even shows some favorable effects on promoting cell spreading. The technique reported here is a versatile approach to develop biomedical coatings with different functions., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

It is acknowledged that ideal implant coatings should possess micro/nano-textured surface, have good interfacial bonding, and can release bioactive elements. In this study, we fabricated a Zn-incorporated micro/nano-textured surface by one-step high current anodization (HCA) in an aqueous solution with 10 g/L of NaOH and different concentrations of Zn(NO 3 ) 2 (4, 7, and 12 g/L). The control group of Zn-free was fabricated in the electrolyte of 7 g/L Zn(NO 3 ) 2 . Scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and inductively coupled plasma mass spectroscopy (ICP-MS) were used to analyze the morphology, composition, microstructure, and Zn + release kinetics of the micro/nano-textured coatings. The biological properties of the surface structure were evaluated by cytotoxicity assay, cell viability, cytoskeletal assembly and alkaline phosphatase activity. Our results show the micro/nano-textured surface is composed of TiO 2 mesoporous arrays, into which the Zn is demonstrated to be incorporated in the form of ZnO. The Zn content in the surface and release level of Zn 2 + can be tailored through varying Zn(NO 3 ) 2 concentration in the electrolyte. In addition, the surface oxide layers show good interfacial bonding strength to the substrate. Compared with pure Ti and anodized Zn-free samples, the Zn-incorporated surface can upregulate osteoblast functions such as proliferation and alkaline phosphatase activity, which are assayed by MTT and ALP staining experiments, respectively. Collectively, this micro/nano-textured structure combined with high interfacial bonding strength and release of Zn 2 + render the material surface promising as orthopedic implant coatings. [ABSTRACT FROM AUTHOR]

This study investigates the efficiency of carbon nanotubes (CNTs) as reinforcement for polypropylene (PP) for biocompatible application as a function of different surface functionalization of CNTs. PP composites were reinforced using various CNTs: single- and multi-walled carbon nanotubes (SWCNTs, MWCNTs), SWCNTs were covalently functionalized by plasma, for comparison, the MWCNTs were functionalized noncovalently. Different CNTs were incorporated into PP by solution blending. The type of CNTs and surface functionalization affects the mechanical and biocompatibility results significantly. Differences in nanostructure and the chemical compositions, number of functional groups, and structural defects for the CNTs may be the key factors affecting the mechanical properties and biocompatibility of PP nanocomposites compared to the neat PP. Finally, suitable CNTs and surface functionalization of CNTs were selected for making the PP/CNTs composites. [ABSTRACT FROM PUBLISHER]

Abstract: Electrochemical anodization has become a prevalent surface modification method for biomaterials nowadays. In this study we prepared Ni2O3-doped TiO2 nanotubes (NTs) on NiTi alloy using electrochemical anodization method and explored its suitability for biomedical applications. Morphology, composition and microstructure of NT films were found to depend on preparation conditions. NT film prepared at 35V, 45°C and 10min had well-defined nanotubular architecture and were composed of TiO2 and a small amount of Ni2O3. Annealing at 450°C, the film remained amorphous structure, with excellent corrosion resistance. At annealing temperatures of 600°C, rutile crystalline was formed thus enhanced the bioactivity of the film. Formation of NT film on the surface of NiTi alloy also increased its wettability, especially for 600°C annealed sample, so the biological response is expected to be improved. Our results indicate that annealing the NT film coated NiTi alloy at 450°C is desirable for cardiovascular applications. This attributes to its advantages such as the eliminated toxic F species, enhanced corrosion resistance and reduced risk of calcification. For orthopedic applications, annealing at 600°C is preferred due to its enhanced corrosion resistance and bioactivity. [Copyright &y& Elsevier]

[Display omitted] • Ta/TC4 alloy layer with scalelike micro/nano-textured surface is prepared by PAST. • Ta-Ti-O NTs with lamellar distribution were anodically grown on Ta/TC4 surface. • Ta-Ti-O NTs show superior cytocompatibility and osteogenic activities due to lamellar NTs and Ta 2 O 5 doping. Bioactive composition and bionic topography are highly desired in the surface design of biomedical implant materials. Herein, Ta-Ti-O nanotubes (NTs) were anodically grown on a tantalum (Ta) alloyed Ti6Al4V (Ta/TC4) surface. Ta/TC4 shows a scalelike surface and (α'+β) microstructure with a thickness of 11.7 μm, while Ta-Ti-O NTs exhibit a lamellar topography with ∼ 1.0 μm in length and 48.6 nm in diameter. Ta-Ti-O NTs group has the lowest water contact angle of ∼ 16.5° compared with TC4, Ta/TC4, and Ti-O NTs grown under the same electrochemical conditions. In vitro assays show that Ta-Ti-O NTs are non-cytotoxicity to MC3T3-E1 osteoblasts and slightly hamper cellular proliferation, but the adhesion and spreading abilities are significantly enhanced than others. The alkaline phosphatase (ALP), collagen type-1 (COL 1), and extracellular matrix (ECM) mineralization levels of osteoblasts on Ta-Ti-O NTs were also improved and further confirmed by osteogenesis-related gene expressions like ALP, COL 1, OPG, and TGF-β1. The superior osteogenic activities of Ta-Ti-O NTs can be mainly ascribed to the combined effect of Ta 2 O 5 doping and the lamellar distribution of NTs. In summary, Ta-Ti-O NTs film with excellent cytocompatibility and osteogenic activities will find its clinical application in the future. [ABSTRACT FROM AUTHOR]

Anodizing behavior of Ta/Ti6Al4V (Ta/TC4) alloy layer with scalelike micro/nano-textured surface and (α ' + β) microstructure in fluoride-containing ethylene glycol electrolyte has been investigated. Ta/TC4 was prepared by plasma surface Ta-alloying of TC4 alloy. In anodization, by turning applied voltage, time, H 2 O concentration, and NH 4 F concentration, Ta-Ti-O nanotube arrays/nanopore arrays (NTAs/NPAs) with different thicknesses and diameters can be grown on Ta/TC4 surface. Higher voltage, higher NH 4 F concentration, and longer anodization time are conducive to forming NTAs rather than NPAs. The excessive H 2 O accelerates the chemical dissolution of NTAs and leads to uneven distribution of NTAs diameter and decline of thickness. The NPAs formed at the initial stage of anodization will be replaced by NTAs retaining the (α ' + β) characteristic of Ta/TC4 with anodization continues, so does the scalelike micro/nano-textured structure on Ta/TC4 surface. The electrochemical tests in the DMEM solution reveal the superior corrosion resistance of Ta/TC4 than TC4. However, Ta-Ti-O NTAs show deteriorated corrosion resistance which may be ascribed to the large specific surface area and massive lamellar gaps between Ta-Ti-O NTAs. • Ta/TC4 alloy layer with scalelike micro/nano-textured structure is prepared. • Ta-Ti-O nanotubes/nanopores with different dimensions can be anodically grown. • The anodic microstructure affects the morphology of anodized nanostructures. • The excellent corrosion resistance of Ta/TC4 is weakened after anodization. [ABSTRACT FROM AUTHOR]

The major drawback of magnesium alloys in biomedical applications is the rapid degradation rate and the lack of biological activity. In this study, TiO 2 nanotubes were fabricated on the surface of AZ91D magnesium alloy (TiO 2 -Mg) to overcome such limitations. The corrosion behavior of TiO 2 -Mg nanotubes was studied in simulated body fluid solution using open circuit potentials (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests. The high polarization resistance and open circuit potentials of TiO 2 -Mg nanotubes indicate the formation of highly stable TiO 2 layer in simulated body fluid than that of titanium layer on magnesium alloy (Ti-Mg). TiO 2 nanotubes on AZ91D magnesium alloy (AZ91D) can effectively decrease the degradation rate of magnesium alloy, thus can be further applied in orthopedic implants. [ABSTRACT FROM AUTHOR]

Biomedical titanium (Ti) implants with good anti-infective, osteogenic, and angiogenic properties are in great demand. SrTiO 3 nanotubes (NTs) are embedded with silver oxide (Ag 2 O) nanoparticles (NPs) (denoted as NT-Sr-Ag) by a hydrothermal treatment of TiO 2 NTs containing Ag 2 O NPs (denoted as NT-Ag) in a Sr(OH) 2 solution. The morphology, composition, microstructure, ion release phenomenon, as well as antibacterial, osteogenic, and angiogenic activities are investigated in details. During the hydrothermal treatment, the amorphous TiO 2 in the NTs morphs into cubic SrTiO 3 gradually and the ordered nanotubular architecture is preserved. Some Ag 2 O NPs are incorporated into the structure although some of them dissolve in the solution. Long-term bacterial resistance against Staphylococcus aureus is observed as a result of the prolonged and controllable Ag + release. NT-Sr-Ag can also release Sr 2 + similarly to stimulate osteoblasts to secrete the vascular endothelial growth factor (VEGF). Both the released Sr 2 + and secreted VEGF upregulate the alkaline phosphatase (ALP) activity and extracellular matrix mineralization of osteoblasts. Furthermore, better angiogenic activity is observed when endothelial cells are cultured in NT-Sr-Ag conditioned media when compared with that in NT-Ag conditioned media, which is believed to be ascribed to the positive regulation of VEGF secretion of Sr 2 + . NT-2Sr-Ag and NT-3Sr-Ag (Hydrothermal treatment for 2 and 3 h, respectively) exhibit excellent antibacterial, osteogenic, and angiogenic activities and are promising in biomedical implants. [ABSTRACT FROM AUTHOR]

Although long nanotubes with a large specific surface area are desirable in many applications, it is difficult to produce long Ni-Ti-O nanotubes on nearly equiatomic NiTi alloy in fluoride (F)-containing ethylene glycol (EG) by anodization. In this work, a new electrolyte composed of EG, H 2 O, and HCl is designed and adopted to fabricate long nanopores rather than nanotubes on the NiTi alloy. By applying an anodization voltage of 10 V to the EG solutions containing 5.0–11.0 vol% H 2 O and 0.125–0.75 M HCl, Ni-Ti-O nanopores with a diameter of about 70 nm are produced. The nanopore length increases almost linearly with anodization time and by optimizing the experimental conditions, nanopores with a length of 160 μm can be prepared. [ABSTRACT FROM AUTHOR]

We fabricate Ni–Ti–O NTs with different size on NiTi alloy through varying anodization voltages and evaluate their corrosion behavior, Ni release, and cytocompatibility. Our results show the NTs influence the corrosion behavior and cytocompatibility of NiTi alloy in a size-dependent manner. Worse corrosion resistance and more Ni release are observed from large NTs because of their high specific surface area. However, cytocompatibility is improved after anodization especially for the sample anodized at 25 V. These results thus indicate the release level of Ni ions from NiTi alloy is well tolerated by osteoblasts and surface nanotubular structure contribute to its cytocompatibility. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we report on the formation of in situ self-organized Cu-containing nanotube and nanopore oxide structures by one-pot anodizing of Ti- and TiAl-related alloys in NH4F containing ethylene glycol electrolytes. The microstructure of the as-doped bi/ternary alloys and resultant nanotubular or nanoporous oxide layers was characterized using X-ray diffraction (XRD), field-emission-scanning electron microscope (FE-SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). It reveals that the Ti–10Cu alloy is mainly composed of Ti3Cu, TiCu and Ti phases while the TiAl–10Cu comprises TiAl, TiCu, Ti and Al phases. After anodization, the Cu containing self-aligned nanotubular and nanoporous structure can be successfully formed on Ti–10Cu and TiAl–10Cu, respectively. XPS result indicates that the residual Cu embedded in the form of CuO on the as-formed oxide nanostructures. The antibacterial tests (spread plate counting and fluorescence staining) show that, all antibacterial rates for Escherichia coli and Staphylococcus aureus can reach to above 99% on surface of anodized TiCu–O and TiAlCu–O. Moreover, both of the as-anodized TiCu–O and TiAlCu–O exhibit no cytotoxicity to the growth of osteoblast cells. These in situ self-organized Cu-containing nano-tubular and nano-pore oxide structures integrating with favorable antimicrobial activity and excellent biological property will find potential applications in fields of antimicrobial materials, biomedical or implanting devices, etc. [Copyright &y& Elsevier]

Microscopic topography and chemical composition of implant surface play critical roles in cellular response. In this work, Ta 2 O 5 -doped TiO 2 nanotubes (Ta 2 O 5 /TiO 2 NTs) were prepared on Ti6Al4V (TC4) to improve its cytocompatibility to endothelial cells. Firstly, a Ta diffusion layer on TC4 (Ta/TC4) was designed by plasma surface Ta-alloying. Then, a Ta 2 O 5 /TiO 2 NTs film was grown on Ta/TC4 by anodization. The surface morphology, phase composition, and microstructure of the obtained samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Ta incorporation leads to the lamellar microstructure (α' + β) of Ta/TC4 and the lamellar distribution of Ta 2 O 5 /TiO 2 NTs. In vitro assays demonstrate that the synergistic effect of Ta 2 O 5 addition and biomimetic nanostructure is responsible for the enhanced proliferation, adhesion, cytoskeletal assembly, and spreading of endothelial cells on Ta 2 O 5 /TiO 2 NTs. The excellent cytocompatibility of Ta 2 O 5 /TiO 2 NTs highlights its potential in biomedical applications. • Ta 2 O 5 /TiO 2 NTs were prepared by plasma surface Ta-alloying and anodization. • Ta-Ti6Al4V with (α '+ β) microstructure leads to lamellar Ta 2 O 5 /TiO 2 NTs. • Ta 2 O 5 /TiO 2 NTs show improved cytocompatibility to endothelial cells. [ABSTRACT FROM AUTHOR]