Dmitry Zablotsky

Numerical investigation of thermo-magneto-solutal flow of ferrocolloid through ordered and disordered permeable membranes

We explore the mechanism of ferroparticle transfer in porous structures in the conditions of simultaneous action of the thermal gradient and the magnetic field. We show that when a ferrocolloid saturated porous matrix is placed in a homogeneous magnetic field the grains of the porous frame notably distort the uniformity of the internal field by creating sharp gradients in the vicinity of the interface. On the other hand, the application of the temperature gradient creates an imbalance of the ferroparticle concentration in the bulk of the porous structure due to colloidal thermophoresis. The combination of the imbalance of concentration of the magnetic nanoparticles and the internal gradients of the magnetic field creates a magnetic force and convective flow of solution through the porous structure. We report the results of the pore-scale numerical simulations of the ferrocolloid thermo-magneto-solutal flow in geometrically simple ordered and disordered permeable structures and membranes with different porosity.Graphical abstract

Iron oxide/oleic acid magnetic nanoparticles possessing biologically active choline derivatives: Synthesis, morphology, antitumor, and antimicrobial properties

Abstract In recent years, synthetic magnetic nanoparticles have made a major contribution to biomedicine. Interest in iron oxide magnetic nanoparticles conditioned by the fact that they are nontoxic, and possess the unique opportunity to deliver medicines to certain organs by external magnetic field. We have developed a synthetic procedure, which is based on binding of the first biologically active substance with the magnetic core, and subsequent immobilization of another biologically active substance (ligand) on the modified surface of nanoparticles thus creating plasma membrane-like structures. Using the proposed methodology, we have obtained new nontoxic magnetic nanoparticles, functionalized with pre-synthesized aliphatic and heterocyclic choline analogues, and determined their composition, structure, and size by different physicochemical methods. Interaction of the obtained nanoparticles with tumor cells and normal fibroblasts, as well as, bacterial cells and fungi has been evaluated. The resulting magnetic fluids revealed superparamagnetic properties and affected tumor and microbial cells.

Phase Composition and Morphology of Tungsten Oxide Nanoparticles Produced via a Pyrolytic Process

The chemical synthesis is a leading route for the purposeful design of nanomaterials, whereas the tungsten oxides are employed in a variety of special applications. The production of nanomaterials by traditional synthetic methods is still a cumbersome multistep procedure. Here we propose an improved method to produce tungsten oxide nanoparticles via a pyrolytic process. A tungsten-containing precursor was prepared by liquid extraction using n-trioctylamine (C8H17)3N solution in toluene. We have shown that the conditions of thermal treatment of the W-based precursor determine the crystalline structure and nanomorphology of the final product. Monoclinic WO3 nanocrystallites are produced conducting the pyrolysis above 450 °C. The proposed method is a facile and versatile route to produce and control the phase composition and morphology of tungsten oxide-based nanomaterials.