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Silica/polycaprolactone Nanofiber Scaffold Variants for Human Periosteal Cell Growth
摘要： Polycaprolactone (PCL) nanofiber scaffolds with attached cadaveric human periosteum or its cells were investigated in this study as a tissue-engineering approach to repair non-union injuries of bone. Addition of silica nanoparticles (silica or nSiO2) to PCL scaffolds was examined for effects on the growth of human periosteal cells in vitro and in vivo. Electrospun PCL nanofiber (nanoPCL) scaffolds were fabricated with different silica content (0, 0.5 and 1.0 wt%) and utilized as substrates on which periosteal cells were seeded. Human periosteal cell growth analyzed in vitro over 21 days with a PrestoBlue? viability assay increased as a function of culture time on each of the three different silica/nanoPCL scaffolds. Cadaveric periosteum attached to nanoPCL scaffolds with or without silica was wrapped around allograft bone and implanted for 10 or 20 weeks in athymic (nude) mice. Histological and immunohistochemical analyses of these experiments in vivo confirmed the presence of viable cells populating the constructs after their retrieval from host mice. Osterix, a marker for osteoblasts, increased in retrieved constructs over time and indicated remodeling of the underlying allograft bone. Summary results suggest that silica/nanoPCL scaffolds may be utilized as substrates for periosteal cell and tissue expansion to augment and support clinical applications for treatment and healing of bone defects, including segmental bone injuries and non-unions.
关键词： nanoPCL,bone defects,silica,Periosteum,tissue engineering
更新于2025-09-23 15:19:57
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Synthesis of high-purity zircon, zirconia, and silica nanopowders from local zircon sand
摘要： High-purity zircon (ZrSiO4) nanopowder was successfully produced from Indonesian natural zircon sand using a low-cost purification approach via magnetic separation, immersion in HCl, and reaction with NaOH, followed by a top-down nanosizing process using wet ball-milling for 10 hours and annealing at 200 °C for 2 hours. Furthermore, polymorph zirconia (ZrO2 – amorphous, tetragonal, and monoclinic) and silica (SiO2 – amorphous and cristobalite) nanopowders were also successfully derived from the purified zircon powder using a bottom-up method via alkali fusion and co-precipitation processes followed by calcination. The crystallite size of the powders was estimated from X-ray diffraction (XRD) data analysis to give 40, 31, 61, and 149 nm, respectively, for the zircon, tetragonal- and monoclinic-zirconia, and cristobalite. Microstructural characteristics of the zircon, silica, and zirconia nanopowders were revealed in transmission electron microscopy (TEM) images which confirmed that the average sizes of the particles were in a good agreement with the XRD estimated values.
关键词： zircon,tetragonal zirconia,amorphous silica,nanopowder,cristobalite,monoclinic zirconia
更新于2025-09-23 15:19:57
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An improved class of fluorescent silica nanoparticles for indirect immunofluorescence detection of MCF-7?cells
摘要： In this work, we have developed an efficient method based on silica fluorescent dye-doped nanoparticles and second antibody for cancer cell labeling. The dye-doped silica nanoparticles were synthesized by the reverse microemulsion method with the conjugate of 3-aminopropyltriethoxysilane and rhodamine B isothiocynate. A PEG with flexible long chain as the bridge was introduced onto the surface of the nanoparticle via cyanogens bromide method. The second antibody, goat anti-rabbit IgG, was conjugated on the surface of the PEG-terminal modified silica fluorescent nanoparticles by covalent binding to the PEG linkers via the EDC/sulfo-NHS method. The concentrations of goat anti-rabbit IgG covering the nanoparticles were quantified via the Bradford method. The silica fluorescent nanoparticles functionalized with rabbit anti-MUC1 antibody were employed as bioprobes for the recognition of MUC1 protein in human breast carcinoma molecules MCF-7 cells. Compared with fluorescent dye labeled IgG, the fluorescent nanoprobes display dramatically increased photostability.
关键词： MCF-7 cells,Dye-doped silica nanoparticles,Conjugation,Mucin,Bioprobe
更新于2025-09-23 15:19:57
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Preparation of SiC Powders by Carbonthemal Reduction Method at Low Temperature
摘要： The stable slurry was prepared by ball-milling with a certain proportion of silica fume as silicon source, glucose as carbon source and metal niobium (Nb) as additives mixed with alcohol water. After the slurry was dried and pulverized, put the powder into a tubular furnace heated to 650℃ for 2h under nitrogen atmosphere to prepare precursor, the heating rate was 5℃ /min. Treated the precursor under vacuum by carbothermal reduction method to prepare silicon carbide (SiC) powder. The effect of temperature and additive content on the morphology of synthesised silicon carbide and the impurity removal order on product purity were explored. After firing at 1300℃, 1400℃, 1500℃ for 2 h, the 3C-SiC powders are detected, and as the temperature increased, the crystallinity of the product become better. When the content of the additive is 1% of the quality of the silica fume, the particle size of the silicon carbide synthesized at the temperature of 1500℃ is even and the dispersion is better. As for the impurity removal order, removed SiO2 first, then removed C can effectively remove the impurities in the product.
关键词： metal niobium,carbothermal reduction,silica fume,glucose,SiC powders,low temperature
更新于2025-09-23 15:19:57
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Bi <sub/>2</sub> SiO <sub/>5</sub> @g-SiO <sub/>2</sub> upconverting nanoparticles: a bismuth-driven core–shell self-assembly mechanism
摘要： Core–shell systems have attracted increasing interest among the research community in recent years due to their unique properties and structural features, and the development of new synthetic strategies is still a challenge. In this work, we have investigated lanthanide-doped Bi2SiO5 nanocrystal formation inside mesoporous silica nanoparticles (MSNs). The role of both synthesis temperature and concentration of the bismuth precursor impregnated into the MSNs is discussed, showing an unprecedented strategy for the simultaneous stabilization of a crystalline core and a glassy shell. Temperature dependent synchrotron radiation X-ray powder diffraction (SR-XRPD) and high resolution transmission electron microscopy (HR-TEM) analyses allow one to follow the crystalline core growth. A mechanism for the formation of a Bi2SiO5@g-SiO2 core–shell nanosystem is proposed. In addition, the easy tunability of the color output of the upconverting system is demonstrated by means of suitable doping lanthanide ions with potential applications in several fields.
关键词： upconversion luminescence,mesoporous silica,core–shell nanoparticles,bismuth silicate,Bi2SiO5
更新于2025-09-19 17:15:36
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Silicon nitride and silica quarter-wave stacks for low-thermal-noise mirror coatings
摘要： This study investigates a multilayer high reflector with new coating materials for next-generation laser interferometer gravitational wave detectors operated at cryogenic temperatures. We use the plasma-enhanced chemical vapor deposition method to deposit amorphous silicon nitride and silica quarter-wave high-reflector stacks and studied the properties pertinent to the coating thermal noise. Room- and cryogenic-temperature mechanical loss angles of the silicon nitride and silica quarter-wave bilayers are measured using the cantilever ring-down method. We show, for the first time, that the bulk and shear loss angles of the coatings can be obtained from the cantilever ring-down measurement, and we use the bulk and shear losses to calculate the coating thermal noise of silicon nitride and silica high-reflector coatings. The mechanical loss angle of the silicon nitride and silica bilayer is dispersive with a linear weakly positive frequency dependence, and, hence, the coating thermal noise of the high reflectors show a weakly positive frequency dependence in addition to the normal 1/sqrt(f) dependence. The coating thermal noise of the silicon nitride and silica high-reflector stack is compared to the lower limit of the coating thermal noise of the end test mirrors of ET-LF, KAGRA, LIGO Voyager, and the directly measured coating thermal noise of the current coatings of Advanced LIGO. The optical absorption of the silicon nitride and silica high reflector at 1550 nm is 45.9 ppm. Using a multimaterial system composed of seven pairs of ion-beam-sputter deposited Ti:Ta2O5 and silica and nine pairs of silicon nitride and silica on a silicon substrate, the optical absorption can be reduced to 2 ppm, which meets the specification of LIGO Voyager.
关键词： quarter-wave stacks,silica,silicon nitride,gravitational wave detectors,thermal noise,mechanical loss,cryogenic temperatures,optical absorption,mirror coatings
更新于2025-09-19 17:15:36
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Highly selective fluorescence chemosensor based on carbon-dot-aerogel for detection of aniline gas
摘要： Solid-state fluorescence sensing has become a research hotspot because it is simple and convenient in practical operation. In this study, the carbon dots (CDs)-silica aerogel solid fluorescent material was developed for the selective detection of aniline gas. The blue CDs were prepared by one-step simply hydrothermally treating low-cost sawdust, then CDs-silica aerogel composite material with the high specific surface areas and high porosity was prepared by sol-gel method based on abundant hydroxyl groups on the surface of the CDs which can initiate the gelation of tetraethyl orthosilicate. It is capable of selectively distinguishing toxic gaseous aniline with other volatile organic vapors by sensitive fluorescence quenching, and under optimal conditions, the fluorescence quenching efficiency of aniline gas can reach 76.4%. It is expected that our strategy might provide a new approach for developing a low cost, fast and sensitive CDs-based probe for environmental sensing applications.
关键词： Silica aerogel,Fluorescence chemosensor,Aniline gas,Carbon dots
更新于2025-09-19 17:15:36
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Green Waste-Derived Substances Immobilized on SBA-15 Silica: Surface Properties, Adsorbing and Photosensitizing Activities towards Organic and Inorganic Substrates
摘要： Urban wastes are a potential source of environment contamination, especially when they are not properly disposed. Nowadays, researchers are finding innovative solutions for recycling and reusing wastes in order to favour a sustainable development from the viewpoint of circular economy. In this context, the lignin-like fraction of biomass derived from Green Compost is a cost-effective source of soluble Bio-Based Substances (BBS-GC), namely complex macromolecules/supramolecular aggregates characterized by adsorbing and photosensitizing properties. In this work BBS-GC were immobilized on a silica support (SBA-15) and the chemico-physical properties of the resulting hybrid material (BBS-SBA) were analysed by zeta-potential measurements, nitrogen adsorption at 77K and micro-calorimetric techniques. Successively, the BBS-SBA photosensitizing and adsorption abilities were tested. Adsorption in the dark of Rhodamine B and Orange II on BBS-SBA and their degradation upon irradiation under simulated solar light were shown, together with the formation of hydroxyl radicals detected by Electron Paramagnetic Resonance spectroscopy. Furthermore, the adsorption of six inorganic ions (Al, Ni, Mn, As, Hg, Cr) on BBS-SBA was studied in pure water at two different pH values and in a landfill leachate, showing the good potential of this kind of materials in the removal of wastewater contaminants.
关键词： photocatalysis,wastewater treatment,orange,adsorption,waste-derived substances,hybrid silica,rhodamine
更新于2025-09-19 17:15:36
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Stray millimeter-wave radiation loads on ITER fused silica windows
摘要： In ITER, the window assemblies will be subjected to the combination of loads due to stray radiation and neutron streaming. Therefore, adequate tests are needed to qualify the windows for the hostile environmental conditions. In ITER, two main systems will generate high power waves in the millimeter range: the Collective Thomson Scattering (CTS) system, with a total power of 1 MW at 60 GHz, and the Electron Cyclotron Resonant Heating (ECRH) system, with a maximum power of 20 MW at 170 GHz. In particular operating conditions, a significant power fraction can be deflected in other ports as stray radiation. High levels of stray radiation could damage diagnostic windows that are safety relevant components. The radiation absorbed by the fused silica window assemblies on ports #11 and #12 have been evaluated in detail. The possible effects of gamma and neutron flux on the dielectric permittivity and loss tangent, determining the absorption, have also been reviewed.
关键词： ECRH,Vacuum windows,Stray radiation,Fused silica,CTS
更新于2025-09-19 17:15:36
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Third-order nonlinearity and optical limiting properties of sol–gel-based bromophenol blue dye immobilized in silica–titania nanohybrid
摘要： Silica–titania (ST) nanohybrid and bromophenol blue (BPB) immobilized ST nanohybrid matrix are synthesized by low-temperature sol–gel route. The in?uence of BPB on the structural, morphological, and nonlinear optical properties of silica–titania nanohybrid was investigated by fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), atomic force microscopy (AFM), and z-scan technique. FTIR analysis con?rms the chemical bonding between hydrophobic BPB dye species and hydrophilic type ST nanohybrid matrix. TEM and AFM analysis shows that the synthesized immobilized nanohybrid has inter-dispersed structure with average particle size of 0.8 ± 0.3 nm, smooth morphology, and low average surface roughness ~4.57 nm. The immobilization of BPB greatly improves the nonlinear refraction response and the nonlinear refractive index increases from 4.8 × 10–9 cm2/W to 451.9 × 10–9 cm2/W. Reverse saturable absorption is observed in both BPB and BPB/ST nanohybrid. However, the magnitude of nonlinear absorption coef?cient in BPB/ST is lower than the BPB dye due to the occurrence of saturable absorption of the ST matrix. The optical limiting (OL) behavior of the BPB/ST nanohybrid reveals the low OL threshold at 0.33 kW/cm2. The synthesized BPB/ST nanohybrid has potential as an optical limiters for safety of photonic and optoelectronic devices under low-powered CW laser.
关键词： Optoelectronics,Silica–titania nanohybrid,Saturable absorption,Bromophenol blue dye,Structural analysis
更新于2025-09-19 17:15:36