Thousands of different nanoparticles (NPs) involve in our daily life with various origins from food, cosmetics, drugs, etc. It is believed that decreasing the size of materials up to nanometer levels ...can facilitate their unfavorable absorption since they can pass the natural barriers of live tissues and organs even, they can go across the relatively impermeable membranes. The interaction of these NPs with the biological environment disturbs the natural functions of cells and its components and cause health issues. In the lack of the detailed and comprehensive standard protocols about the toxicity of NPs materials, their control, and effects, this review study focuses on the current research literature about the related factors in toxicity of NPs such as size, concentration, etc. with an emphasis on metal and metal oxide nanoparticles. The goal of the study is to highlight their potential hazard and the advancement of green non-cytotoxic nanomaterials with safe threshold dose levels to resolve the toxicity issues. This study supports the NPs design along with minimizing the adverse effects of nanoparticles especially those used in biological treatments.
The propose of this review was to summarize the advances in multi-scale surface technology of titanium implants to accelerate the osseointegration process. The several multi-scaled methods used for ...improving wettability, roughness, and bioactivity of implant surfaces are reviewed. In addition, macro-scale methods (e.g., 3D printing (3DP) and laser surface texturing (LST)), micro-scale (e.g., grit-blasting, acid-etching, and Sand-blasted, Large-grit, and Acid-etching (SLA)) and nano-scale methods (e.g., plasma-spraying and anodization) are also discussed, and these surfaces are known to have favorable properties in clinical applications. Functionalized coatings with organic and non-organic loadings suggest good prospects for the future of modern biotechnology. Nevertheless, because of high cost and low clinical validation, these partial coatings have not been commercially available so far. A large number of in vitro and in vivo investigations are necessary in order to obtain in-depth exploration about the efficiency of functional implant surfaces. The prospective titanium implants should possess the optimum chemistry, bionic characteristics, and standardized modern topographies to achieve rapid osseointegration.
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•Grain refinement and TiZn2 intermetallic complex were found in the stir zone.•Dislocation and α″ martensite enhanced the microhardness of the composite surface.•The composite surface ...promoted cell adhesion, proliferation and osteogenic differentiation.•The composite surface inhibited bacterial adhesion and growth.
Osteogenic differentiation and antibacterial property are two-core requirements for bone implants, but typically they are not compatible. Zinc (Zn) as a common bioactive material is widely used in the medical field. A balance between antibacterial and osteogenic activity can be achieved at appropriate Zn concentration. In this study, the TNTZ/Zn micro/nano-composites were prepared by doping Zn nanoparticles onto Ti-35Nb-2Ta-3Zr (TNTZ) surface through the friction stir processing (FSP) technique. The results of material characterization revealed the homogeneous distribution of Zn, the presence of α″ martensite, and the increase in microhardness in the stir zone. Due to the solid metallurgical bonding between Zn NPs and substrate, Zn ions were released slowly and may be biologically responsive through body fluid corrosion. In terms of biological activity, the expression of adhesion-related protein vinculin and osteogenic differentiation genes were up-regulated by TNTZ/Zn, which improved the early adhesion and osteogenic differentiation of bone marrow stromal stem cells. Besides, TNTZ/Zn presented excellent antibacterial properties, and direct contact with the fine grain surface containing Zn NPs may be the dominant mechanism. TNTZ/Zn micro/nano-composites have excellent mechanical properties, osteogenic differentiation and antibacterial properties, providing an efficient strategy for titanium alloy surface modification and showing tremendous potential in dental applications.
Porous titanium is a functional structural material with certain porosity, which is prepared from titanium powder and titanium fiber. In order to study the porosity, phase structure, microstructure, ...sintering mechanism and mechanical properties of porous titanium obtained by spark plasma sintering of a Ti powder⁻fiber mixture at different sintering temperatures, a spherical titanium powder (D
of 160 μm) was prepared via plasma rotating electrode processing, and titanium fiber (average wire diameter of fiber of 110 μm) was prepared by drawing, and they were mixed as raw materials according to different mass ratios. Porous titanium with a fiber⁻powder composite porous structure was prepared by spark plasma sintering at sintering temperatures of 800 °C, 900 °C and 1000 °C under a sintering pressure of 20 MPa. The results showed that there were no new phases occurring in porous titanium with porosity of 1.24⁻24.6% after sintering. Titanium fiber and titanium powder were sintered using powder/powder, powder/fiber and fiber/fiber regimes to form composite pore structures. The mass transfer mechanism of the sintered neck was a diffusion-dominated material migration mechanism during sintering. At higher sintering temperatures, the grain size was larger, and the fiber (800 °C; 10⁻20 μm) was finer than the powder (800 °C; 10⁻92 μm). The stress⁻strain curve of porous titanium showed no obvious yield point, and the compressive strength was higher at higher sintering temperatures. The results of this paper can provide data reference for the preparation of porous titanium obtained by spark plasma sintering of a Ti powder⁻fiber mixture.
In recent years, significant advances in the field of medical materials have begun to emerge, especially in nanotechnology. The modern area of nanostructured implants possesses wide applications in ...various medical implants including their dental use. Nano-surface functions present substantial resolutions to medical obstacles through improved biomaterial proficiency, innovative dental-implant designs, and surface design procedures, such as nanoscale adhesive surfaces, bio-chemical anodization, and surface modification technique. This work covers dental implant history, nanotechnological advances, and its development that includes a description, basic properties, and the related results of composites and surface morphology, and the different types of nanomaterials used in dental implants. Significant attempts have been made over the last few decades to strengthen osteointegration and prevent bacterial attachment to the implant surfaces. The micro and nano-topography of the hierarchical surface orchestrate the biological reactions of implants and may solve the problems associated with implant-tissue issues. This research investigates the implant articles from 1964 to 2021, which offers a brief description of the nanostructured biomaterials to enhance dental implants’ performance and may open new frontiers in the advancement of implant technology.
An aluminum-based metal-organic framework material MIL-96(Al) was prepared by solvent-thermal synthesis method, and by adding multi-walled carbon nanotubes (MWCNTs) in the preparation process, ...MWCNT/MIL-96(Al) composite adsorbent was synthesized for the first time. The morphology of the adsorbents was discussed by scanning electron microscopy (SEM). In adsorption experiments under different working conditions, MIL-96(Al) exhibited a stable equilibrium adsorption capacity, while the addition of only 0.50% mass fraction of multi-walled carbon nanotubes increased equilibrium adsorption capacity by approximately 30%. The enhancement ratio of six composite adsorbents compared to MIL-96(Al) in equilibrium adsorption capacities was almost constant under different working conditions. The adsorption rate of MIL-96(Al) could reach up to 0.573 g g−1 h, while that of the composite adsorbents under the same conditions was 0.763 g g−1 h. MIL-96(Al) could be completely desorbed within 40 min at 110 °C, and the optimal desorption temperature of MWCNT/MIL-96(Al) was reduced to 100 °C. The cyclic stability of the seven adsorbents was also confirmed through cyclic regeneration experiments. The experimental results indicated that the MWCNT/MIL-96(Al) composite adsorbent was a potential adsorbent for solar-driven atmospheric water harvesting in arid regions.
The synthetic process and performance of MWCNT/MIL-96(Al) based on atmospheric water harvesting. Display omitted
•The equilibrium adsorption capacity of MIL-96(Al) is extremely stable at all temperature and humidity conditions.•MIL-96(Al) exhibited a stable equilibrium adsorption capacity, while the addition of only 0.50% mass fraction of multi-walled carbon nanotubes increased equilibrium adsorption capacity by approximately 33%.•When the mass fraction of MWCNTs was 0.40%–0.60%, the property increase in equilibrium adsorption capacity brought by the composite was more stable across different conditions.•MIL-96(Al) could complete the desorption process of all water molecules within 40 min at 110 °C, and the optimal desorption temperature of MWCNT/MIL-96(Al) was reduced to 100 °C.•After 20 times of cyclic adsorption performance tests, none of seven adsorbents showed decay in adsorption performance.
With high hydrothermal stability and hydrophilicity, MIL-100(Fe) has potential applications in sorption-based atmospheric water harvesting (SAWH). This paper reports the water vapor adsorption ...properties of MIL-100(Fe) prepared by solvent and solvent-free methods. Performance tests show that the MIL-100(Fe) prepared by solvent-free method has more advantages. To further improve the performance of the adsorbent, the composite adsorbent MgCl2@MIL-100(Fe) was obtained by impregnating MIL-100(Fe) with MgCl2 solution. The results showed that the composite adsorbent had good adsorption performance, desorption properties, and fast adsorption rate. The equilibrium adsorption capacities of the composite adsorbent with 35% salt content were 0.533 g/g and 1.062 g/g at 25 °C with the relative humidity (RH) of 35% and 80%, respectively, which were 1.51 times and 1.74 times of the adsorption capacity of MIL-100(Fe) under the same working conditions. This showed that the solvent-free synthesized MIL-100(Fe) and its composite adsorbent have the potential for application in SAWH.
This paper compares the solvent-free synthesis of MIL-100(Fe) with the hydrothermal synthesis of MIL-100(Fe) with solvent. Then, by evaluating the various properties (characterizations, adsorption performance, cycle stability, preparation cost, etc.) of materials prepared by two different methods, it is determined whether the MIL-100(Fe) prepared by the solvent-free synthesis method is more suitable for water vapor adsorption. Eventually, to further improve the adsorption performance of this material, MIL-100(Fe) was impregnated in MgCl2 solution to develop a new composite adsorbent MgCl2@MIL-100(Fe) for further study. Display omitted
•The solvent-free synthesized MIL-100(Fe) has excellent adsorption performance and cycle stability.•The composite adsorbent MgCl2@MIL-100(Fe) has rapid adsorption kinetics.•The adsorption capacity of the composite adsorbent with an MgCl2 mass fraction of 35% can reach 1.062 g/g.•The composite adsorbent has good water absorption at low relative humidity, which can reach 0.533 g/g.
In this paper, the metal-organic framework material MIL-100(Fe) was synthesized by hydrothermal method, and then combined with LiCl, CaCl2, and MgCl2 by the impregnation method, and the resulting ...composite materials were named M/LiCl, M/CaCl2, and M/MgCl2. MIL-100(Fe) and its composites were characterized by SEM, BET, XRD, and TGA, and the open adsorption properties at different temperatures and RH were explored, and the desorption properties and cycle stability of the materials were explored. Experiments show that the equilibrium adsorption capacity of MIL-100(Fe) is greatly enhanced by the combination with hygroscopic salt, and the equilibrium adsorption capacity of M/LiCl, M/CaCl2, and M/MgCl2 is 1.77, 1.03 and 0.58 g/g, respectively, which is 4.4, 2.6 and 1.5 times that of MIL-100(Fe) under the condition of 25 °C and 65% RH. When the ambient RH increases from 35% to 65% at 25 °C, the equilibrium adsorption capacity of MIL-100(Fe) increases from 0.35 g/g to 0.40 g/g, and the equilibrium adsorption capacity of M/LiCl increases from 0.97 g/g to 1.77 g/g. The influence of temperature on the equilibrium adsorption capacity of the adsorbent is negligible, but the increase in temperature will greatly increase the initial adsorption rate of the adsorbent. When RH is 50%, the equilibrium adsorption capacity of M/MgCl2 at 15–35 °C is 0.51∼0.54 g/g, and the maximum adsorption rate is 2.52∼5.18 g/(g·100 min). MIL-100(Fe) and its composites can be completely desorbed after desorption at 130 °C for 70 min, the desorption rate is ≥98%, and the water vapor residue is ≤0.02 g/g. M/CaCl2 showed good cycling stability, and the adsorption capacity after 11 cycles was 94% of the first.
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•Composites collapse at higher temperatures compared with MIL-100(Fe).•Compared with M/LiCl and M/CaCl2, M/LiCl has best equilibrium adsorption capacity.•Under 25 °C and 65% RH, the adsorption capacities of M/LiCl, M/CaCl2, and M/MgCl2 were 1.77, 1.03, and 0.58 g/g.•The composite M/CaCl2 showed good cycling stability.
Titanium alloys produced by additive manufacturing show excellent mechanical properties at room temperature. However, their deformation behavior at low temperature is still not fully understood. In ...this study, the microstructural evolution and tensile behavior of the near-α titanium alloy Ti-6.5Al-2Zr-Mo-V (TA15), fabricated via laser powder bed fusion (LPBF), were determined at both 25 °C and −196 °C. The LPBFed TA15 alloy shows the microstructure of α laths and acicular α′ martensite due to the rapid cooling rate during LPBF processing. Pyramidal <c+a> slip and numerous twins, including nano-twins and triple twins, were activated at cryogenic temperature, leading to the high ultimate tensile strength (UTS) up to 1750±8 MPa and yield strength (YS) up to 1548±25 MPa, which is higher than the strength at room temperature (YS∼1103 MPa, UTS∼1281 MPa). The dominant deformation mechanism changes from dislocation slip to twinning with decreasing temperature, leading to uniform deformation with an elongation of 5.2±0.1 %. The results can guide the control of the microstructure of LPBFed near-α titanium alloys at cryogenic temperature.
•The LPBFed TA15 showed excellent tensile strength (YS∼1548 MPa, UTS∼ 1750 MPa, elongation∼5.2±0.1 %) at −196 °C.•A large number of 101̅1<101̅2> nano-twins, including the nanotwins and triple twins, were activated at cryogenic temperature.•The dominant strengthening mechanism varies from dislocation strengthening to twin boundary strengthening.
An AlCoCuFeTi high-entropy alloy with excellent wear resistance and high hardness was successfully produced by arc melting. The effects of annealing on the microstructure, nanomechanical behaviors, ...tribological properties, and corrosion resistance were systematically investigated. The results showed that the AlCoCuFeTi consisted of a Co-enriched L21 phase, a Cu-enriched FCC phase, and a (Fe, Ti)-enriched Laves phase. Annealing promoted the formation of FCC and Laves phases but decreased the volume fraction of the L21 phase. The high hardness of AlCoCuFeTi is attributed to the formation of L21 and Laves phases. The highest hardness (14.1 ± 1.3 GPa) and reduced Young's modulus (256 ± 11 GPa) were achieved in the 1100 °C annealed and 900 °C annealed specimens, respectively. All specimens exhibited excellent wear resistance compared to typical HEAs due to the mild-oxidational wear mechanism. The 1100 °C annealed specimen possessed the highest elastic strain to failure (H/Er) and yield pressure (H3/Er2), corresponding to its best-measured wear resistance. The segregation of Cu led to galvanic corrosion during the polarization tests, and the area ratio of cathode to anode (Ac/Aa) determined the corrosion rate. The 1100 °C annealed specimen exhibited good corrosion resistance due to its low Ac/Aa value.
•The AlCoCuFeTi high-entropy alloy exhibits high hardness due to the formation of L21 and Laves phases.•Annealing promotes the formation of FCC and Laves phase while decreasing the volume fraction of L21 phase.•The AlCoCuFeTi high-entropy alloy obtains an outstanding wear resistance because of the mild-oxidational wear mechanism.
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