Nanosized Silicon Dioxide Research Articles

Inhalable porous particles as dual micro-nano carriers demonstrating efficient lung drug delivery for treatment of tuberculosis

Inhalation therapy treating severe infectious disease is among the more complex and emerging topics in controlled drug release. Micron-sized carriers are needed to deposit drugs into the lower airways, while nano-sized carriers are of preference for cell targeting. Here, we present a novel and versatile strategy using micron-sized spherical particles with an excellent aerodynamic profile that dissolve in the lung fluid to ultimately generate nanoparticles enabling to enhance both extra- and intra-cellular drug delivery (i.e., dual micro-nano inhalation strategy). The spherical particles are synthesised through the condensation of nano-sized amorphous silicon dioxide resulting in high surface area, disordered mesoporous silica particles (MSPs) with monodispersed size of 2.43 μm. Clofazimine (CLZ), a drug shown to be effective against multidrug-resistant tuberculosis, was encapsulated in the MSPs obtaining a dry powder formulation with high respirable fraction (F.P.F. <5 μm of 50%) without the need of additional excipients. DSC, XRPD, and Nitrogen adsorption-desorption indicate that the drug was fully amorphous when confined in the nano-sized pores (9–10 nm) of the MSPs (shelf-life of 20 months at 4 °C). Once deposited in the lung, the CLZ-MSPs exhibited a dual action. Firstly, the nanoconfinement within the MSPs enabled a drastic dissolution enhancement of CLZ in simulated lung fluid (i.e., 16-fold higher than the free drug), increasing mycobacterial killing than CLZ alone (p = 0.0262) and reaching concentrations above the minimum bactericidal concentration (MBC) against biofilms of M. tuberculosis (i.e., targeting extracellular bacteria). The released CLZ permeated but was highly retained in a Calu-3 respiratory epithelium model, suggesting a high local drug concentration within the lung tissue minimizing risk for systemic side effects. Secondly, the micron-sized drug carriers spontaneously dissolve in simulated lung fluid into nano-sized drug carriers (shown by Nano-FTIR), delivering high CLZ cargo inside macrophages and drastically decreasing the mycobacterial burden inside macrophages (i.e., targeting intracellular bacteria). Safety studies showed neither measurable toxicity on macrophages nor Calu-3 cells, nor impaired epithelial integrity. The dissolved MSPs also did not show haemolytic effect on human erythrocytes. In a nutshell, this study presents a low-cost, stable and non-invasive dried powder formulation based on a dual micro-nano carrier to efficiently deliver drug to the lungs overcoming technological and practical challenges for global healthcare.

Production Silicon Carbide Based on Micro and Nano-Sized Silicon Dioxide in Conditions of Thermal Plasma Energy

Production Silicon Carbide Based on Micro and Nano-Sized Silicon Dioxide in Conditions of Thermal Plasma Energy

Thermal enhancement of nano-fluidic transport confined between disk and cone both rotating with distinct angular velocities and heat transfer

PurposeThis paper aims to study the fluid flow and heat transfer within the Casson nanofluid confined between disk and cone both rotating with distinct velocities. For a comprehensive investigation, two distinct nano-size particles, namely, silicon dioxide and silicon carbide, are submerged in ethanol taken as the base fluid.Design/methodology/approachThis paper explores the disk and cone contraption mostly encountered for viscosity measurement in various industrial applications such as lubrication industry, hydraulic brakes, pharmaceutical industry, petroleum and gas industry and chemical industry.FindingsIt is worth mentioning here that the radially varying temperature profile at the disk surface is taken into the account. The effect of prominent emerging parameters on velocity fields and temperature distribution are studied graphically, while bar graphs are drawn to examine the physical quantities of industrial interest such as surface drag force and heat transfer rate at disk and cone.Originality/valueTo the best of the authors’ knowledge, no study in literature exists that discusses the thermal enhancement of nano-fluidic transport confined between disk and cone both rotating with distinct angular velocities with heat transfer.

Synthesis of Hydrophobic Nanosized Silicon Dioxide with a Spherical Particle Shape and Its Application in Fire-Extinguishing Powder Compositions Based on Struvite.

Textural and morphological features of hydrophobic silicon dioxide, obtained by the hydrolysis of tetraethoxysilane in an ammonia medium followed by modification of a spherical SiO2 particles surface with a hydrophobic polymethylhydrosiloxane, were studied in this work. The size of silicon dioxide particles was controlled during preparation based on the Stöber process by variation of the amount of water (mol) in relation to other components. The ratio of components, synthesis time and amount of the hydrophobizing agent were determined to obtain superhydrophobic monodisperse silicon dioxide with a spherical particle size of 50-400 nm and a contact angle of more than 150°. In the case of the struvite example, it was demonstrated that the application of spherical- shaped hydrophobic silicon dioxide particles in powder compounds significantly improves the flowability of crystalline hydrates. The functional additive based on the developed silicon dioxide particles makes it possible to implement the use of crystalline hydrates in fire-extinguishing powders, preventing agglomeration and caking processes. The high fire-extinguishing efficiency of the powder composition based on struvite and the developed functional additive has been proven by using thermal analysis methods (TGA/DSC).

Perinatal exposure to foodborne inorganic nanoparticles: A role in the susceptibility to food allergy?

Food allergy (FA) is an inappropriate immune response against dietary antigens. Various environmental factors during perinatal life may alter the establishment of intestinal homeostasis, thereby predisposing individuals to the development of such immune-related diseases. Among these factors, recent studies have emphasized the chronic dietary exposure of the mother to foodborne inorganic nanoparticles (NP) such as nano-sized silicon dioxide (SiO2), titanium dioxide (TiO2) or silver (Ag). Indeed, there is growing evidence that these inorganic agents, used as food additives in various products, as processing aids during food manufacturing or in food contact materials, can cross the placental barrier and reach the developing fetus. Excretion in milk is also suggested, hence continuing to expose the neonate during a critical window of susceptibility. Due to their immunotoxical and biocidal properties, such exposure may disrupt the host-intestinal microbiota's beneficial exchanges and may interfere with intestinal barrier and gut-associated immune system development in fetuses then the neonates. The resulting dysregulated intestinal homeostasis in the infant may significantly impede the induction of oral tolerance, a crucial process of immune unresponsiveness to food antigens. The current review focuses on the possible impacts of perinatal exposure to foodborne NP during pregnancy and early life on the susceptibility to developing FA.

ПОВЫШЕНИЕ ВОДОСТОЙКОСТИ ДРЕВЕСИНЫ ПРОПИТОЧНЫМ СОСТАВОМ НА ОСНОВЕ РАСТИТЕЛЬНОГО МАСЛА С НАНОПОРОШКОМ ДИОКСИДА КРЕМНИЯ

The aim of the work was to develop and study new compositions for the treatment of natural wood based on used vegetable oil with the addition of nanosized silicon oxide to obtain a wood composite with improved properties. Specimens of birch wood were chosen as objects of the study. The basis of the developed impregnating compositions was used frying vegetable oil. The compositions were supplemented with additives of amorphous and crystalline silicon oxide nanopowders at a dosage of 0.01 to 0.5%. To modify wood, a stable suspension of synthesized silicon oxide nanopowders in used sunflower oil was prepared. The processing of wood specimens was carried out by the method of "hot-cold impregnation". The obtained wood composites with the addition of nanosized silicon oxide had improved hydrophobic properties of wood (an increase in the contact angle by 30%), increased moisture and water resistance (by 11 and 14 times, respectively), as well as reduced swelling in the tangential (by 4 times) and radial (5 times) directions in comparison with natural wood after 1 day of testing. The optimal dosage of silicon oxide nanopowders (0.01%) was chosen. A comparative evaluation of the use of amorphous and crystalline silicon oxides in impregnating compositions based on used vegetable oil was carried out using birch wood as an example. Impregnation compositions based on waste vegetable oil have low toxicity and their use makes it possible to dispose of production waste

Automated technology for the production of nanosized silicon dioxide and carbon

The article presents the results of the development of an automated process control system for the production of nanosized silicon and carbon for use in construction in the Arctic zone. The logical and organizational structures have been implemented; measuring instruments and a rational coding classification system have been selected. The machine and non-machine information bases have been worked out.

Hydrophobic nanosilica-stabilized graphite particles for improving thermal conductivity of paraffin wax-based phase-change materials

Phase change materials based on paraffin wax are characterized with low thermal conductivity, which could be improved by the addition of particles of a heat-conducting material, for example, graphite. However, graphite particles agglomerate in molten paraffin wax matrix and settle. In this study, the use of hydrophobic nano-sized silicon dioxide as a stabilizer was considered to obtain stable dispersions of graphite in paraffin wax. Rheological and thermophysical properties of paraffin-based mixtures containing from 1 to 5 vol. % of hydrophobic silica and from 1 to 15 vol. % of graphite were investigated. At the concentration of 3 vol. %, silica nanoparticles form a percolation structure, which is expressed in the emergence of the yield stress that is capable to prevent the sedimentation of graphite particles introduced into the mixture. It allows obtaining dispersions that are stable both in time and at passage of cooling–heating cycles. The joint influence of silica and graphite fillers on the ability of paraffin wax to accumulate and conduct heat was investigated. Thermal conductivity of dispersions at the introduction of graphite increases according to the Maxwell's model, which allows improving the thermal conductivity on 33 % from initial value at the introduction of 15 vol. % of graphite.

Biocidal Activity of Polyester Fabrics Modified with SiO2 Nps

The inorganic nano-sized silicon dioxide modify polyester fabrics using IR dyeing machine was constructed. Chemical activation method with alkali hydrolysis of the fabric was done to facilitate the binding affinity of SiO2 NPs via carboxylic and hydroxyl groups created on the fabric surface. The morphological structure of the treated fabrics was investigated by field-emission scanning electron microscopy (FE-SEM). Dispersive X-ray spectroscopy (EDX) of the untreated and treated polyester fabrics was measured. Fourier transformed infrared spectroscopy (FTIR) of the untreated and treated fabrics was elucidated. TEM of the used silicon dioxide nano particles was monitored. Thermogravimetric analysis (TGA) and UV protection and of the treated fabrics were studied. Antimicrobial activity of finished polyester fabrics containing SiO2 NPs was tested against Gram-positive (Staphylococcus aureus), Gram-negative (Escherichia coli), and pathogenic fungi (Candida albicans and Aspergillus flavus). The results indicate that the nano-silica has an excellent effect on antimicrobial activity and good protection of both UVA and UVB even after ten washing cycles, indicating the excellent laundering durability. The performance of treated fibers to be used as medical textile was determined by radar chart area.

Effect of Nanosized Silicon Dioxide Additive on Plasma Electrolytic Oxidation Coatings Fabricated on Aluminium

Effect of Nanosized Silicon Dioxide Additive on Plasma Electrolytic Oxidation Coatings Fabricated on Aluminium

Properties of a double-layer EMW-absorbing structure containing a graded nano-sized absorbent combing extruded and sprayed 3D printing

The ever-increasing electromagnetic wave (EMW) energy and its reflections may impair human health and information security. An ordinary EMW-absorbing structure usually exhibits limited EMW-reflecting capacity given its ungraded structure in both the micro and macro scales. In this study, four nano-sized graded absorbents are explored by wrapping carbonyl-iron powder with nano-sized silicon dioxide. The micro-scale wrapping effects are assessed via a scanning electron microscopy experiment to identify the best sample, including a 5 wt% coupling agent and a 10 wt% dispersant in CIP ethanol. The 10 mm thick concrete matching layer containing the graded absorbent is built using spraying methodology, and the 15 mm thick absorption layer is fabricated using extruding methodology. The mercury intrusion porosimetry experiments show that the sprayed matching layer incurs maximum porosity at 19.8% while the 3D extruded layer ensures the minimum porosity at 11.13%, strengthening the laminar grading effect to improve the EMW impedance matching. The Naval Research Laboratory experiments corroborate that double-layer structures improve the EMW-reflecting capacity compared to their single-absorption-layer counterparts and that the double-layer element containing the best wrapping effect absorbent yields the best reflection loss value, with a minimum of −14.7 dB and a 9.72 GHz effective bandwidth. The EMW-reflecting mechanism for the novel graded double-layer structure containing the graded nano-sized absorbent is then summarized. Theoretical calculations using the transform line theory suggest that a 15 mm absorbing layer and a 15 mm impedance matching layer is specified as the most optimized configuration, with −10.47 dB in average reflection, −15.18 dB in maximum RL, and 9.56 GHz in effective bandwidth.

INFLUENCE OF NANOSIZED SILICA OXIDE SUSPENSION ON NITRIC OXIDE PRODUCTION IN RATS TESTES DURING CHRONIC NITRATE-FLUORIDE INTOXICATION

In the Poltava region of Ukraine there is a high possibility of combined excessive intake of nitrates and fluorides, since the waters of the Buchaksʹkii aquifer are rich in fluorine ions, moreover, the Poltava region is a region with a developed agriculture.&#x0D; The purpose of this work is to determine the effect of nanosized silicon oxide suspension on the changes in the activity of nitric oxide cycle components, components, and, namely the total activity of NO-synthases (NOS), the activity of constitutive forms of NOS (cNOS), inducible form of NOS (iNOS), nitrate reductase, nitrite reductase, nitrite reductase, nitrite reductase in the testes of rats under the conditions of chronic combined nitrate-fluorodide intoxication.&#x0D; Materials and methods. The study was conducted on 15 mature male Wistar rats weighing 200-253 g. The animals were randomly divided into 3 groups of 5 animals in each. The first group received daily saline solution through a gastric tube. The second group (chronic combined intoxication group) received sodium nitrate and fluoride in a dosage of 500 mg / kg of sodium nitrate and 10 mg / kg of sodium fluoride. The third group against the background of chronic combined intoxication modelling additionally received a suspension of nanosized silicon oxide is a dosage of 100 mg / kg of active substance.&#x0D; Results. Chronic combined intoxication increases total NOS activity by 65.9% compared to the control group. The increase in NO production by NOS is the result of a 4-fold increase in iNOS activity, since the activity of cNOS under these conditions does not change significantly. Nitrite reductase-dependent NO production increases by 66.7%, nitrate reductase activity increases by 77.8%. Nitrite content in the testes homogenate grows in 2.17 times. Hydrolytic cleavage of L-arginine by arginase increases in 2.88 times. The introduction of nanosized silicon oxide suspension under the conditions of chronic combined intoxication did not statistically significantly change the total NOS activity and cNOS activity compared to the group exposed to chronic intoxication. However, iNOS activity reduces in 3.69 times. Nitrate reductase activity decreases in 1.6 times, while nitrite reductase activity decreases in 45%. The activity of arginases lowered in 2.38 times. The nitrite content of the testes cut down by 23.6%.&#x0D; Conclusions. Chronic combined nitrate-fluoride intoxication leads to the development of hyperproduction of nitric oxide in the testes of rats by activating the inducible isoform of NO synthase and nitrite reductases. The use of nanosized silica suspension during chronic combined intoxication is an effective method to correct nitric oxide overproduction in the testes of rats.

Study of SiO2 nanopowder produced by plasma arc method

The work is devoted to the study of the plasma arc method of obtaining nanosized silicon oxide from natural raw materials from Russian fields, such as diatomite of Kamyshlovsk deposit (Sverdlovsk region), the quartzite of Chupinsk deposit (Republic of Karelia), quartz sand of Tugansk deposit (Tomsk region). The method of transmission electron microscopy was used to study the morphology. Brunauer-Emmett-Teller method was used to study the surface. The main structural and morphological characteristics of the obtained nanoparticles were determined. The particles of nanoscale SiO2 obtained by the plasma arc method spherical shape, the size distribution 10–300 nm, the specific surface area 37–71 m2·g−1.

CORRECTION OF OXIDATIVE STRESS IN GASTRIC MUCOSA OF RATS BY ENTEROSORBENTS OF DIFFERENT CLASSES DURING CHRONIC NITRATE FLUORIDE INTOXICATION

In some regions of Ukraine, the environmental conditions can be considered as threatening for the life of people and animals. There has been reported excessive accumulation of nitrates in the bodies of humans and animals with food and drinking water in regions with developed agriculture. At the same time, in regions with developed chemical and metallurgical (especially aluminium production) industries, additional contamination of drinking water with excess fluoride has been found out to take place. Thus, simultaneous excess intake of nitrates and fluorides into the human body cannot be excluded. The purpose of this work is to determine the effect of nanosized silica, Carboline and hydrolytic lignin suspensions on the production of superoxide anion radical (О2∙-), the activity of antioxidant enzymes, the content of oxidative-modified proteins and the concentration of primary products of lipid peroxidation (POL). Materials and methods. All biochemical studies were carried out in 10% gastric mucosa homogenates of the rats. The study assessed the activity of superoxide dismutase (SOD), catalase, content of diene conjugates, octadiene conjugates, trien conjugates, the content of oxidative-modified proteins (OMP) and О2∙- production. Results. Chronic nitrate-fluoride intoxication leads to an increase in the basic О2∙- production with a simultaneous decrease in the activities of SOD and catalase. The content of primary POL and OMB increases during chronic intoxication. Usage of enterosorbent suspensions reduces О2∙- production, restores functioning of antioxidant enzymes, lowered the content of primary POL and OMP. Conclusions. Chronic nitrate-fluoride intoxication leads to oxidative damage to the phospholipids of biological membranes and the protein structures of the gastric mucosa. Suspensions of nanosized silicon oxide, carboline and lignin are effective means for correcting oxidative damage to the gastric mucosa during chronic nitrate-fluoride intoxication.

The Method of Obtaining Amorphous Nanosized Silicon Dioxide from Rice Production Waste

The method of using rice husk, which is a rice production waste, as a raw material for the production of silicon dioxide as an alternative to synthetic silicon dioxide – aerosil is considered. A low-energy process for extracting silicon dioxide and cellulose from the husk by alkaline digestion in an NaOH solution was proposed, followed by treating the black liquor with an acid solution and calcining the precipitate at 575 °C during 5 hours. The yield of inorganic products from rice husk is determined based on the ash content of the pulp. It was shown that the product obtained mainly consists of silicon dioxide (SiO2) of amorphous structure, has an average particle size of less than 100 nm, which makes it possible to characterize it as nanosilica. At the same time, silicon dioxide consists of 51.7 % silicon and 48.3% oxygen against theoretical amounts of 30.4 % silicon and 69.6 % oxygen, respectively. The output of silicon dioxide is 8.8 % by weight of rice husk. At the same time, the process allows to obtain another valuable nanocellulose product.

Particle reinforced open porous anodizing layers on AA5005

The present work deals with the target aimed design of anodic oxide films on AA5005 by modified phosphoric acid anodizing and reinforcement by subsequent impregnation with nanosized silicon dioxide by chemical nanotechnology. The authors show the influence of the anodizing time on the oxide layer thickness, the pore diameter and the morphology. It is revealed that silicon dioxide nanoparticles are successful when incorporated into the open structure pores of the layer. The anodizing and the incorporation process were carried out wet on wet. Complementary electrochemical measurements show the potential of the modified oxide layer in view of corrosion protection despite their deliberated open porosity.

Synthesis of Nano-Sized Silicon Oxide, Iron Oxide and Carbonates from Chrysotile Asbestos.

The objectives of this study were to investigate the physicochemical dissolution of chrysotile asbestos and to synthesize nano-sized materials and carbonate minerals from the asbestos via acid dissolution and pH changes. Chrysotile asbestos powder was dissolved in 3 different acids, HCl, HThe objectives of this study were to investigate the physicochemical dissolution of chrysotile asbestos and to synthesize nano-sized materials and carbonate minerals from the asbestos via acid dissolution and pH changes. Chrysotile asbestos powder was dissolved in 3 different acids, HCl, H₂SO₄, and HNO₃, and the solutions were then titrated using NH₄OH and reacted with CO₂. The residual material and precipitates were examined with XRD and TEM-EDS. ICP-AES analysis was also used to investigate the chemical makeup of the solution. The concentration of Mg in the solution was about 1,280 mg/L. The chrysotile became noncrystalline silica after acid treatment (pH = 0). At pH 8.6 and 9.5, the precipitates were amorphous iron oxide and nesquehonite [Mg(HCO3)(OH)·2(H₂O)] after reaction with CO₂. The particle size of the precipitates ranged from 2 to 500 nm. These results indicate that dissolution of chrysotile asbestos using HCl, H₂SO4, and HNO3 can chemically alter chrysotile fibers. Also, the dissolved materials can be used as precursors for other materials such as silica, iron oxide, and carbonates. This process may be useful for the synthesis of silica and iron oxides and for mineral carbonation for carbon sequestration. SO4, and HNO₃, and the solutions were then titrated using NH4OH and reacted with CO₂. The residual material and precipitates were examined with XRD and TEM-EDS. ICP-AES analysis was also used to investigate the chemical makeup of the solution. The concentration of Mg in the solution was about 1,280 mg/L. The chrysotile became noncrystalline silica after acid treatment (pH = 0). At pH 8.6 and 9.5, the precipitates were amorphous iron oxide and nesquehonite [Mg(HCO₃)(OH)·2(H₂O)] after reaction with CO₂. The particle size of the precipitates ranged from 2 to 500 nm. These results indicate that dissolution of chrysotile asbestos using HCl, H₂SO₄, and HNO3 can chemically alter chrysotile fibers. Also, the dissolved materials can be used as precursors for other materials such as silica, iron oxide, and carbonates. This process may be useful for the synthesis of silica and iron oxides and for mineral carbonation for carbon sequestration.

Excess conductivity analysis in YBa2Cu3O7−d added with SiO2 nanoparticles and nanowires: Comparative study

The effect of nanosized silicon oxide nanoparticles (denoted NP-SiO2) and nanowires (denoted NW-SiO2) additions during the final processing stage on electrical fluctuation conductivity of polycrystalline YBa2Cu3O[Formula: see text] (Y-123 for brevity) in the mean field region has been reported. Series of samples were synthesized in air using a standard solid-state reaction technique by adding nanosized entities up to 0.5 wt.%. Phases, microstructure and superconductivity properties have been systematically investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM) and electrical measurements. TEM investigations show the presence of inhomogeneities embedded in the superconducting matrix along with the presence of columnar defects in the case of SiO2 nanoparticles added samples, however nanowires tend to agglomerate by entangling with each other in the intergrain regions. The fluctuation conductivity was analyzed as a function of reduced temperature using the Aslamazov–Larkin model. Using the Lawrence–Doniach equations, the Ginzburg–Landau (GL) number (NG) and equations, the coherence length, the effective layer thickness, the lower critical field [Formula: see text], the upper critical field [Formula: see text] and the critical current density [Formula: see text] were estimated. It was found that the addition of an optimum concentration of SiO2 nanomaterials, that depends on the shape, effectively controlled the microstructure, the grains coupling and hence improved the physical properties of Y-123 compound.

Wear resistance of the oxide layers formed on AK9pch silumin by microarc oxidation in an electrolyte modified by silicon dioxide nanoparticles

The structure, the phase composition, the surface morphology, the microhardness, and the tribological characteristics of the oxide layers of various thicknesses formed on AK9pch alloy during microarc oxidation are studied. A positive influence of a small addition (5 g/L) of nanosized silicon dioxide to an electrolyte on these characteristics of the oxide layers is revealed.

Получение стержневых структур карбида кремния капельным и автоклавным методами

Preparation of silicon carbide by traditional methods involves considerable energy and economic costs, so the search for alternative technologies of the synthesis is of the great interest. Carbon nanomaterials are actively investigated as a carbon source to reduce the temperature of synthesis. This paper presents the results of an experimental study of the morphology, elemental composition and crystal structure of structures obtained from colloidal solutions of short (l ~ 500 nm) carbon nanotubes and nano-sized (~ 7 nm) amorphous silicon dioxide by drying droplet and autoclave methods. The formation of rod-like structures was revealed at certain critical concentrations of initial components. It was found that the dynamic conditions of the drying droplets determine a synthesis of rod-like structures at room temperature at 2-3 times larger than at the autoclave at a temperature of about 180 °C. The elemental analysis of samples showed a high percentage of carbon and silicon atoms. The presence of the polytype 4-H SiC phase in the rod-like structures was revealed by the X-ray diffractometry. A model of the active charged center of short carbon nanotubes that provides the possibility of Si-C, Si-O-C and C-Si-O-C covalent bonds formation was offered based on numerical calculations. The drying droplet method is suitable for a quick (10-20 minutes) local synthesis of a small amount of rod-like structures with a minimum energy consumption. The autoclave allows to synthesize gram quantities for a long time (a few days). Both methods are low temperature in the comparison with the widely used in practice.