Voltammetric Behavior, Identifying and Quantitatively Determining Iron-Based Nanoparticles, and Evaluating Their Stability in Simulated Solutions of Gastric Juice.

The electrochemical behavior of Fe3O4 nanoparticles, iron nanoparticles coated with carbon, and diazonium salts by voltammetry methods using a carbon paste electrode (CPE) has been studied. There has been developed a voltammetric method for identifying and quantifying solid-phase iron-based nanoparticles in the background electrolyte of 0.02 mole/dm3 Trilon B (pH 3.5) with the use of the CPE. Investigations of nanoparticles' stability with various coatings in a simulated solution of gastric juice have been carried out. Nanoparticles stability has been evaluated on the basis of determining Fe(III) ions in a simulated solution after contacting with nanoparticles within different periods of time using the method of inversion voltammetry. It has been shown that nanoparticles coated with carbon and salts of arendiazonium are the most resistant to aggressive media.

The Simultaneous Voltammetric Determination of Aflatoxins В1 and М1 on a Glassy-Carbon Electrode.

For the first time, the possibility of using stripping voltammetry for the simultaneous determination of aflatoxins В1 and М1 on a glassy-carbon electrode has been shown. The influence of various factors (Еэ, τэ, w, and the nature of the background electrolyte) on the potential and magnitude of the oxidation current of mycotoxins has been estimated. Working conditions for voltammetric determination and reproducibility of analytical signals for two mycotoxins have been selected. The mutual influence of aflatoxins В1 and М1 on the value of analytical signals in their simultaneous presence has been studied. It has been found that, in the range of their detectable contents, the presence of aflatoxin В1 reduces the analytical signal of aflatoxin М1 by 45-50%, but the linearity of the calibration dependence is preserved. The content of aflatoxin М1 in determination of aflatoxin B1 does not exert a significant effect in the range of 10-15%. Based on the results obtained, a procedure has been proposed for determining the content of aflatoxins В1 and М1 in their joint presence in milk by voltammetry in the concentration ranges 2 × 10-3 ÷ 2 × 10-1 mg/dm3 and 2 × 10-4 ÷ 2 × 10-2 mg/dm3, respectively (Sr not more than 18%).

Cell-IQ visualization of motility, cell mass, and osteogenic differentiation of multipotent mesenchymal stromal cells cultured with relief calcium phosphate coating.

The Cell-IQ continuous surveillance system allowed us to establish the following changes in a 14- day culture in vitro: a twofold suppression of the directional migration of multipotent mesenchymal stromal cells of human adipose tissue (MMSC-AT) towards the samples with a microarc calcium phosphate (CP) coating from synthetic hydroxyapatite; a tenfold decrease in the cell mass on the interphase with the samples, which was accompanied by a slight reduction in the expression of membrane determinants of stromal stem cells; and an enhancement of their osteogenic differentiation (osteocalcin secretion and mineralized matrix formation) on the 21st day of the study. Calcium phosphate particles, but not the calcium and phosphorus ions, may trigger the phenotypic transformation of the MMSC-AT behavior in vitro.

Imbalance of morphofunctional responses of Jurkat T lymphoblasts at short-term culturing with relief zinc- or copper-containing calcium phosphate coating on titanium.

Morphofunctional response of Jurkat T cells that were cultured for 24 h on substrates prepared from commercially pure titanium with relief microarc bilateral calcium phosphate coating containing copper or zinc was studied. Changes in the concentration of essential trace elements contained in this coating can cause significant imbalance of molecular processes of differentiation, secretion, apoptosis, and necrosis and reduce tumor cell survival.

Colony-forming activity of unipotent hemopoietic precursors under the effect of nanosized ferrites in a constant magnetic field in vitro.

We studied in vitro effect of ferrimagnetic nanoparticles in a dose of 3 mg/liter (10 maximum permissible concentrations) on colony-forming capacity of bone marrow granulocytic and monocytic precursors in a constant magnetic field at magnetic field intensity of 200 Oe. We tested powders obtained by the methods of electrical explosion of conductors (magnetite and a mixture of hematite with magnetite) or mechanochemical synthesis (cobalt ferrite). According to electron microscopy, size of particles was within 6-65 nm. Specific effect of nanopowders on functional properties of hemopoietic and stromal cells were demonstrated; this effect was not related to dissolution of these powders, but had a complex nature. It depends on the size and magnetic characteristics of powder particles, the route and dose of administration, and the presence of external magnetic field. It was emphasized that in multicellular systems a reaction of committed hemopoietic precursors mediated via cells (factors) of microenvironment cannot be excluded, the state of this system varying in different individuals and under different conditions. Our data open new vistas for the creation and targeted use of nanosized materials and technologies for individual therapy in the context of personalized medicine.

[Electrochemical methods of control of iodine contents in drinks]. / Elektrokhimicheskie metody dlia kontrolia soderzhaniia ioda v napitkakh.

The simple and express methods of determination of iodide ions (0.01-0.20 mg/decimeter3) in iodine-enriched drinks by potentiometry and inversion voltamperometry were developed. The studies on influencing a storage time hermetically packaged carbonated beverages, a storage time of the depressurized drinks, stuff of ware on the contents of iodine in drinks are held.