H2O2 is known to be one of the initiators provoking biomolecules (lipids and proteins) oxidation and cell mutation and death. In this context, molecules, which can react with H2O2 without generating ...free radicals such as hydroxyl radicals (·OH), are of special interest as effective preventive antioxidants. In the present study, we report on GdVO4:Eu3+ nanoparticles (NPs) as prospective preventive nanozymes. Synthesized GdVO4:Eu3+ NPs were characterized by TEM, HR-TEM, XRD, SAXS, and XPS methods. It has been revealed that in water solutions GdVO4:Eu3+ NPs are in the form of individual crystalline spheroids with l = 12.1 ± 1.23 nm and d = 5.76 ± 0.68 nm. Using the optical spectroscopy technique, the possibility for Fenton- and CAT-like reactions in water solutions containing GdVO4:Eu3+ NPs has been analyzed. The protective effect of GdVO4:Eu3+ NPs from H2O2-induced oxidative stress has been estimated using rat hepatocytes and analyzing changes in cells’ mitochondrial potential. It was concluded that the main mechanism of H2O2 decomposition both in aqueous solutions and biological milieu is rather associated with CAT-like reactions that ensure the V4+/V5+ and V3+/V4+ redox cycling.
H 2 O 2 is known to be one of the initiators provoking biomolecules (lipids and proteins) oxidation and cell mutation and death. In this context, molecules, which can react with H 2 O 2 without ...generating free radicals such as hydroxyl radicals (·OH), are of special interest as effective preventive antioxidants. In the present study, we report on GdVO 4 :Eu 3+ nanoparticles (NPs) as prospective preventive nanozymes. Synthesized GdVO 4 :Eu 3+ NPs were characterized by TEM, HR-TEM, XRD, SAXS, and XPS methods. It has been revealed that in water solutions GdVO 4 :Eu 3+ NPs are in the form of individual crystalline spheroids with 𝑙 = 12.1 ± 1.23 nm and d = 5.76 ± 0.68 nm. Using the optical spectroscopy technique, the possibility for Fenton- and CAT-like reactions in water solutions containing GdVO 4 :Eu 3+ NPs has been analyzed. The protective effect of GdVO 4 :Eu 3+ NPs from H 2 O 2 -induced oxidative stress has been estimated using rat hepatocytes and analyzing changes in cells’ mitochondrial potential. It was concluded that the main mechanism of H 2 O 2 decomposition both in aqueous solutions and biological milieu is rather associated with CAT-like reactions that ensure the V 4+ /V 5+ and V 3+ /V 4+ redox cycling.
Controlling particle dispersity is of huge importance for practical applications in nanoscience and technology. The analysis of small‐angle scattering of X‐rays and neutrons for strongly polydisperse ...particulate systems is considered from the point of view of describing the type of size distribution function without applying classical regularization approaches. This article presents the development of a method for determining the polydispersity parameters of nanoobjects, based on the analysis of the ratio of various moments of the size distribution function, which are proportional to different invariants of the scattering curve. The use of the unified exponential/power‐law approximation to describe small‐angle scattering data makes it possible to determine the type of distribution, the average size and the spread. The possibilities of the method were tested for several hydrosols of metallic nanoparticles.
This article introduces a generalized approach to determine polydispersity characteristics from small‐angle scattering analysis based on the Beaucage model without numerical integration of experimental data.
Small-angle neutron scattering was applied for the structure characterization of commercial detonation nanodiamond (DND) suspensions. Two reproducible structural levels corresponding to DND particles ...(characteristic size ≈ 4 nm) and their developed clusters (characteristic size ≈ 100 nm) showed high size polydispersity. The contrast variation (based on mixtures of light and heavy water) was used to check up the inner structure of DND particles and compare it with the data of the previous analogous experiments. The fractal nature of the observed clusters is discussed in terms of a unique mechanism of the cluster growth in DND suspensions during their synthesis. The structural peculiarities of “light” and “heavy” cluster fractions separated by centrifugation showed the same cluster type at different size scale. The structure–factor effect on the scattering from the concentrated suspensions of “light” and “heavy” clusters is considered to characterize the cluster–cluster interaction in solutions.
This paper reports the results of the comparative structural characterization of detonation nanodiamond particles and their aggregates in hydrosols and hydrogels by small-angle scattering (SAS) ...techniques. The data from different neutron and X-ray (synchrotron radiation) diffractometers cover a wide range of momentum transfer and show multilevel structure organizations at the size scale from 1 to 1000 nm and higher. For this purpose, in addition to the conventional SAS techniques the methods of very small-angle and ultrasmall-angle neutron scattering were applied. The fraction of nanodiamond particles in the aggregates is determined. A complex two-step mechanism of nanodiamond cluster association into a network during the sol–gel transition is revealed. It is assumed that a reason for the reversibility of this process is a different compactness of the corresponding structural levels defined by different fractal organizations.
Small-angle X-ray and neutron scattering was applied for the structural characterization of aggregates in water dispersions of fullerene C
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prepared by dialysis method and its conjugate with amino ...acid arginine. Two compounds are also compared with respect to their toxic properties. Experiments on the cytotoxicity of these systems on the A549, HepG2 and HeLa cells showed no toxic effects of the dispersions.
The structure of detonation nanodiamond aqueous dispersions grafted by europium or gadolinium atoms was investigated by small-angle neutron scattering over a wide size scale from 1 to 3000 nm. ...Similar to the previous studies of nanodiamond suspensions, a strong association of the particle into developed aggregates was revealed. While the characteristic aggregate size depends on the modification of the dispersions and varies in a wide interval of 35-1500 nm, the fractal character of clusters of nanodiamond particles (packed in a specialized branched form with a fractal dimension of 2.4) remains unchanged independent of the cluster size. The effect of the aggregate size increase upon grafting is considered as a basis for the stability reduction mechanism at the microstructural level.
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