Hydrate Nanoparticles Research Articles

Synthesis, characterization and evaluation of antioxidant properties of catechin hydrate nanoparticles

Catechin hydrate (CH), is an important phyto compound, reported to have potential therapeutic activity for prevention and treatment of various central nervous system (CNS) disorders. However, its therapeutic action is limited by their low oral bioavailability, poor stability and intestinal absorption, therefore, development of a targeted nanoparticle based carrier system which can overcome its physicochemical limitations and can enhance its biological activity is required. The objective of the present study was to formulate nanoparticle based formulation by ionic gelation method for catechin hydrate. After optimizing the formulation by statistical tool, further, characterization results showed zeta average particle size of 68.76 ± 1.72 nm along with polydispersibility index of 0.174 ± 0.081 and zeta potential of −5.32 mV. Moreover, TEM analysis also confirmed its nanometric size range (range of 61.8–128 nm) and FT – IR scan showed no bond formation between polymers and loaded extract (CH). The in vitro compound release kinetics showed a typical linear diffusion profile and cytotoxicity analysis done on NB41A3 cell lines results exhibited the cell viability of 89.5 ± 0.25% in catechin loaded nanoparticles (CH NPs) whereas, it is 82.7 ± 0.34% in CH indicating negligible toxicity in nanoparticle based formulation. The stability testing was done for CH NPs after 8 weeks, and results revealed minimal degradation of catechin. Lastly, the antioxidant activities estimated through DPPH (2, 2–Diphenyl-1-picrylhydrazyl-hydrate), Nitric oxide (NO) and Hydrogen peroxide (H2O2) scavenging assays revealed that CH NPs have higher and prolonged anti-oxidant activity in comparison with CH.

Role of Water During Crystallization of Amorphous Cobalt Phosphate Nanoparticles

The transformation of amorphous precursors into crystalline solids and the associated mechanisms are still poorly understood. We illuminate the formation and reactivity of an amorphous cobalt phosphate hydrate precursor and the role of water for its crystallization process. Amorphous cobalt phosphate hydrate nanoparticles (ACP) with diameters of ∼20 nm were prepared in the absence of additives from aqueous solutions at low concentrations and with short reaction times. To avoid the kinetically controlled transformation of metastable ACP into crystalline Co3(PO4)2 × 8 H2O (CPO) its separation must be fast. The crystallinity of ACP could be controlled through the temperature during precipitation. A second amorphous phase (HT-ACP) containing less water and anhydrous Co3(PO4)2 was formed at higher temperature by the release of coordinating water. ACP contains approximately five molecules of structural water per formula unit as determined by thermal analysis (TGA) and quantitative IR spectroscopy. The Co2+ coor...

Interaction grand potential between calcium-silicate-hydrate nanoparticles at the molecular level.

Calcium-silicate-hydrate (or C-S-H), an inosilicate, is the major binding phase in cement pastes and concretes and a porous hydrated material made up of a percolated and dense network of crystalline nanoparticles of a mean apparent spherical diameter of ∼5 nm that are each stacks of multiple C-S-H layers. Interaction forces between these nanoparticles are at the origin of C-S-H chemical, physical, and mechanical properties at the meso- and macroscales. These particle interactions and the resulting properties may be affected significantly by nanoparticle density and environmental conditions such as the temperature, relative humidity, or concentration of chemical species in the bulk solution. In this study, we combined grand canonical Monte Carlo simulations and an extension of the mean force integration method to derive the pair potentials. This approach enables realistic simulation of the physical environment surrounding the C-S-H particles. We thus constructed the pair potentials for C-S-H nanoparticles of defined chemical stoichiometry at 10% relative humidity (RH), varying the relative crystallographic orientations at a constant particle density of ρpart ∼ 2.21 mmol L(-1). We found that cohesion between nanoparticles is affected strongly by both the aspect ratio and the crystallographic misorientation of interacting particles. This method and the findings underscore the importance of accounting for relative dimensions and orientation among C-S-H nanoparticles in descriptions of physical and simulated multiparticle aggregates or mesoscale systems.

Simple preparation and initial characterization of semi-amorphous hollow calcium silicate hydrate nanoparticles by ammonia-hydrothermal-template techniques

Semi-amorphous hollow calcium silicate hydrate nanoparticles (CS10d120Hac) were successfully synthesized via simple ammonia-hydrothermal-template approach (AHT) followed by acid treatment. Results revealed that the newly synthesized samples had homogenous hollow nano-interior wherein the shell wall contained semi-amorphous calcium silicate hydrate. The AHT intensified the formation of a stronger electrostatic interaction (Si–O–Ca) from the weaker electrostatic contact composed of silicate wall-calcium hydroxide interaction (Si–OH–Ca) forming a thin semi-amorphous calcium silicate hydrate shell wall. This is also a convenient way for structural stability of the hollow CS10d120Hac. The CS10d120Hac showed a relatively higher surface area, which is uniquely rare especially if compared with bulk calcium silicate particles. This CS10d120Hac can be selectively functionalized with multiple organic and inorganic groups. Hence, this work may open a new route for the formation of hybrid hollow bio-active particles.

Highly dispersed carbon-supported Pd nanoparticles catalyst synthesized by novel precipitation–reduction method for formic acid electrooxidation

The highly dispersed and ultrafine carbon-supported Pd nanoparticles (Pd/C) catalyst is synthesized by using an improved precipitation–reduction method, which involves in Pd II → PdO·H 2O → Pd 0 reaction path. In the method, palladium oxide hydrate (PdO·H 2O) nanoparticles (NPs) with high dispersion is obtained easily by adjusting solution pH in the presence of 1,4-butylenediphosphonic acid (H 2O 3P-(CH 2) 4-PO 3H 2, BDPA). After NaBH 4 reduction, the resulting Pd/C catalyst possesses high dispersion and small particle size. As a result, the electrochemical measurements indicate that the resulting Pd/C catalyst exhibits significantly high electrochemical active surface area and high electrocatalytic performance for formic acid electrooxidation compared with that prepared by general NaBH 4 reduction method.

Instant Conversion of Air to a Clathrate Hydrate: CO2 Hydrates Directly from Moist Air and Moist CO2(g)

The rapid conversion of vapor mixtures containing the gases CO(2), H(2)S, and HCN to clathrate hydrates was reported recently. The novel method is based on the pulsing of warm vapor mixtures, including a carrier gas, into a cold condensation chamber. With cooling, the vapors, which also include ∼1% water and either tetrahydrofuran or trimethylene oxide as a catalyst, nucleate aqueous solution nanodroplets that, on a millisecond time scale, crystallize as hydrate nanoparticles that consume 100% of the water. Humid air approximates the content of mixtures used successfully in the vapor-to-hydrate conversions. FTIR spectra are examined for gas hydrates formed directly from air and air enriched with CO(2), as well as hydrate particles for which CO(2)(g) serves as both guest and aerosol medium. In each instance all of the water in the condensed phase converts to a clathrate hydrate. The subsecond ether-catalyzed formation of the hydrates near 230 K requires only a few percent of the CO(2) pressure used in conventional processes that yield fractional amounts of gas hydrates on an hour time scale in the same temperature range.

Hydration Kinetics and Microstructure Development of Normal and CaCl2-Accelerated Tricalcium Silicate Pastes

Microstructure development and the kinetics of hydration of pure tricalcium silicate (C3S) and CaCl2-accelerated C3S pastes were investigated by performing isothermal calorimetry and in situ small-angle neutron scattering (SANS) measurements on parallel specimens during the first few days of hydration, as well as on 28-day old specimens hydrated under the same curing conditions (water/cement ratio = 0.5, 20 °C). Calorimetry experiments were also performed over a range of hydration temperatures from 10 to 40 °C. The calorimetry data were analyzed by applying a previously described boundary nucleation and growth model. The model indicates that CaCl2 significantly increases the rate of nucleation of hydration product on the surface of the C3S particles but has relatively little effect on the product growth rate. The SANS measurements indicate that the composition and density of the calcium−silicate−hydrate (C−S−H) nanoparticles is unchanged by the addition of CaCl2. However, in the CaCl2-accelerated paste th...

Synthesis of Magnetic Nanobiomaterials and Its Biological Effects

Iron oxides and its hydrate nanoparticles, for example, nanoFe3O4 and nanoFe3O4 with hydroxyl, were synthesized by hydrothermal method, their sizes and features are evaluated by infrared spectra and Scanning Electron Microscope (SEM) etc. The dimensions of these nanoparticles produced are about 50-120 nm. In the investigation of influence of nanoFe3O4 and nanoFe3O4 with hydroxyl on crystalline states of amino acid molecules, their crystalline forms are different to that of pure amino acid molecules. The positions and widths of peaks of these nanoparticles in the infrared spectra of absorption are changed largely relative to that of pure amino acid molecules. From the experiments of microscope observation and infrared spectra of re-crytalline amino acids we see that the nanoFe3O4 and nanoFe3O4 with hydroxyl can change the structure of amino acid molecules. To study the toxicity of synthesized nanoparticles, the MTT (3-(4,5-dimethyl-thiazol 2-yl)-2,5 diphenyltetrazolium bromide) assay was used. The OD value (Optical Density) was used to calculated RGR (Relative Generation Rate) of cells, which determined the grade of cytotoxicity. The RGR of nanoparticles of iron oxide and its hydrate are about 1 to 2, which indicate that they have a lower toxicity.

The Biological Effect of Iron Oxide and Its Hydrate Nanoparticles

Iron oxide and its hydrate nanoparticles were synthesized by hydrothermal method and confirmed by infrared and SEM (Scanning Electron Microscope) et al. The dimensions of the nanoparticles are about 50-120 nm. The crystalline form of iron oxide nanoparticles is like globosity while its hydrate rod. Amino acids intermingling with the synthesized nanoparticles were crystallized to investigate the space effect of the nanoparticles. The crystalline forms of crystal are different to that of pure amino acid. The positions and width of the nanoparticles’ peaks in the infrared spectrum are changed too. Microscope observation and infrared spectrum results indicated the nanoparticles had changed the internal structure of amino acids crystal. To considerate the toxicity of the synthesized nanoparticles, MTT (3-(4,5-dimethylthiazol 2-yl)-2,5 diphenyltetrazolium bromide) assay was used to determine their cytotoxicity. The OD value (Optical Density) was used to calculated RGR% (Relative Generation Rate) of cells, which determined the grade of cytotoxicity. The RGR of nanoparticles of iron oxide and its hydrate are about 1 to 2, which indicate they have just low toxicity.

Manipulating the size and morphology of aluminum hydrous oxide nanoparticles by soft-chemistry approaches

We demonstrate control of the size and morphology of aluminum hydrate nanoparticles synthesized by a hydrothermal reaction through manipulating the pH value of the reaction mixture, hydrothermal temperature and the surfactant used. Porous laths were formed under acidic conditions, while the lath-width increased with temperature resulting in the formation of single-crystal porous laths. At neutral or high pH values, porous plates of several nanometers thick were obtained. The pore sizes on both laths and plates were ∼2–3 nm. Stringy lath-shaped nanoparticles were obtained with polyethylene glycol surfactant. The control nanoparticle size and morphology using soft chemical methods is demonstrated. Furthermore, these nanoparticles transformed to γ-alumina nanocrystallites after heating to 673 K, and retained the morphology of the parent boehmite. A detailed characterization of the nanoparticulates and discussion of the mechanism of their formation and subsequent transformation is provided.

Nanoscale Experimental Investigation of Particle Interactions at the Origin of the Cohesion of Cement

Atomic force microscopy has been used to investigate the force at the origin of the cohesion of cement. The cohesion of cement grains is caused by surface forces acting between calcium silicate hydrate nanoparticles in interstitial electrolytic solution. Direct measurement of the interaction between two calcium silicate hydrate surfaces is performed in air and different aqueous solutions. In dry air, starting with the van der Waals forces, the interaction area between calcium silicate hydrate nanoparticles can be estimated. In electrolytic solution, the evolution of these forces is extensively dependent on both surface and solution chemistry. The roles of the calcium hydroxide concentration, pH, and ionic strength are investigated. The force measurements allow us to confirm the pre-eminence of ionic correlation forces in the cohesion of cement.