Search

With the development of nanotechnology, new scientific directions have been initiated and a significant amount of researches has been carried out, dedicated to the creation and search for promising applications in medicine, in particular, oncology, of nanocomposites based on bioinert, biocompatible and bioactive nanoparticle materials and modern chemotherapeutic drugs with different mechanisms of action. These works contain data indicating the advantages to introduce nanocomposite drugs into clinical practice, compared to the traditional use of chemotherapeutic drugs. The research results confirm the priority of works in the field of creation of new nanocomposite chemotherapeutic drugs for use in antitumor therapy and overcoming of drug resistance of malignant cells and neoplasms. The purpose of the review is to generalize and analyze the authors’ experimental works performed at Chuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine, concerning the specifics of the effect of chemotherapeutic drugs with different mechanisms of action and related nanocomposites, on cellular systems and tumors. Such data are relevant to determine promising directions and ways of creation of new effective nanocomposite drugs for use, in particular, in antitumor chemotherapy. At Chuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine, using the chemical engineering method, magnetically sensitive core-shell nanocomposites were synthesized with a multi-level hierarchical nanoarchitecture capable of performing a complex of diagnostic and therapeutic functions with various mechanisms of action, characteristic of medico-biological nanorobots. Their use makes it possible to implement the principle of targeted delivery of antitumor drugs, to carry out real-time local therapy by various methods and MRI diagnosis of the disease, to realize the synergy of treatment with antitumor drugs of different mechanisms of action, to reduce the toxic side effects of oncological drugs on the body. The combination of the above features of nanocomposites, as well as their role in overcoming the drug resistance of cells of malignant neoplasms to cisplatin, testify to the perspective of creation and research of nanocomposite drugs in solving the problem of increase in the efficiency of chemotherapy. [ABSTRACT FROM AUTHOR]

One of the decisive factors that determines the effectiveness of using carbon nanotubes (CNTs) for reinforcing polymer matrices is their uniform distribution in the matrix. It is shown that the percolation threshold in the polychlorotrifluoroethylene (PCTFE)–CNTs system, determined by electrical conductivity data, shifts to lower values with a more uniform distribution of CNTs, while the electrical conductivity increases and correlates with the structure and strength characteristics. Preliminary deagglomeration of CNTs was carried out using ultrasonic treatment in a dispersion of graphene nanoplatelets (GNPs). Three water systems with a CNTs content of 0.5, 0.25, and 0.125 wt.% were dispersed. The GNPs content was 0.1 mass fractions to 1 mass fractions of CNTs for all systems. The dependences of the real (εʹ) and imaginary (εʺ) components of the complex dielectric constant, electrical conductivity (σ) and relative bending strength limit on the volume content of CNTs (ϕ) were found, which have a percolation character. Percolation indices were determined for the dependences σ = f (ϕ), which for the specified concentrations were: flow thresholds (ϕc) − 0.0047, 0.0032, 0.00097 and critical indices (t) − 2.01, 1.78, 1.75, respectively. The most uniform distribution of CNTs, which was achieved at the minimum content of CNTs during dispersion (0.125 wt.% CNTs), corresponds to the maximum value of σ, the lowest percolation threshold, which correlates with the maximum bending strength limit. [ABSTRACT FROM AUTHOR]

Nanocomposites containing components with semiconductor, ferroelectric, and ferromagnetic properties have attracted considerable attention of specialists due to the range of possible applications, including catalysis and electrocatalysis, electrode materials for solar and fuel cells, capacitors, electrical and biosensors, anti-corrosion coatings and much more. In recent years, both fundamental and applied interest in this direction of research is due to the possibility of creating a new type of controlled microwave devices and tools. The aim of the work is to develop methods for the synthesis of nanostructured NiCo composites based on BaTiO3 and TiO2, as well as to find the differences and regularities of their physicochemical properties. Two series of samples with different content of NiCo nanoparticles based on titanium oxide (TiO2) and barium titanate (BaTiO3) were obtained. NiCo particles were obtained by the method of chemical precipitation of nickel and cobalt carbonates in equal parts from a hydrazine hydrate solution at the temperature of 350 K. The results of X-ray phase analysis indicate the chemical purity of the obtained samples. The values of ε′, ε″ at a frequency of 9 GHz for the NiCo/BaTiO3 system are twice as high compared to NiCo/TiO2 for the corresponding values of the NiCo content, which is due to the higher values of ε′, ε″ of the initial barium titanate. Electrical conductivity of NiCo/BaTiO3 system changes by six orders of magnitude, which indicates the formation of a continuous percolation cluster of metal particles on the surface of dielectric BaTiO3 particles. The composites are heat-resistant up to 630K, as shown by the method of thermogravimetry and pronounced magnetic properties. The program for calculating frequency dependences of reflection and absorption coefficients in a complex form has been developed. EMF absorption for composites from the radiation frequency and the position of the minima of these characteristics, which agree satisfactorily with the experiment. The obtained composites can be promising components for obtaining composite systems and paints for protection against electromagnetic radiation. [ABSTRACT FROM AUTHOR]

Copyright of Metallophysics & Advanced Technologies / Metallofizika i Novejsie Tehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nanocomposites containing components with semiconductor, ferroelectric, and ferromagnetic properties have attracted considerable attention of specialists due to the range of possible applications, including catalysis and electrocatalysis, electrode materials for solar and fuel cells, capacitors, electrical and biosensors, anti-corrosion coatings and much more. In recent years, both fundamental and applied interest in this direction of research is due to the possibility of creating a new type of controlled microwave devices and tools. The aim of the work is to develop methods for the synthesis of nanostructured NiCo composites based on BaTiO3 and TiO2, as well as to find the differences and regularities of their physicochemical properties. Two series of samples with different content of NiCo nanoparticles based on titanium oxide (TiO2) and barium titanate (BaTiO3) were obtained. NiCo particles were obtained by the method of chemical precipitation of nickel and cobalt carbonates in equal parts from a hydrazine hydrate solution at the temperature of 350 K. The results of X-ray phase analysis indicate the chemical purity of the obtained samples. The values of ε′, ε″ at a frequency of 9 GHz for the NiCo/BaTiO3 system are twice as high compared to NiCo/TiO2 for the corresponding values of the NiCo content, which is due to the higher values of ε′, ε″ of the initial barium titanate. Electrical conductivity of NiCo/BaTiO3 system changes by six orders of magnitude, which indicates the formation of a continuous percolation cluster of metal particles on the surface of dielectric BaTiO3 particles. The composites are heat-resistant up to 630K, as shown by the method of thermogravimetry and pronounced magnetic properties. The program for calculating frequency dependences of reflection and absorption coefficients in a complex form has been developed. EMF absorption for composites from the radiation frequency and the position of the minima of these characteristics, which agree satisfactorily with the experiment. The obtained composites can be promising components for obtaining composite systems and paints for protection against electromagnetic radiation. [ABSTRACT FROM AUTHOR]