Pleiades Publishing Ltd

The efficiency of zeolite modified with nanostructures (carbon nanotubes) has been studied upon removing anionic organic dye (methyl orange)—sodium 4-(4-dimethylaminophenylazo) benzenesulfonate)— from aqueous media. For quantitative characteristics of the sorption properties of the studied material, the experimental data are analyzed in the linearization coordinates of empirical Langmuir, Temkin, and Dubinin–Radushkevich equations at temperatures of 303, 313, and 323 K. The data correspond best to the following order of adsorption isotherms based on the correlation coefficient: Dubinin–Radushkevich > Temkin > Langmuir. It has been found that adsorption of sodium 4-(4-dimethylaminophenylazo) benzenesulfonate on zeolite, modified with nanostructures is a spontaneous endothermic process. The possibility of a significant increase in the adsorption capacity of zeolites by their volumetric modification by nanostructures is shown. According to the experimentally determined value of the sorption capacity, the studied modified zeolite is 2–5 times higher than the analogs.

This work is dedicated to the synthesis of a GO@Fe3O4@DOX multifunctional nanocomposite composed of graphite oxide, superparamagnetic iron oxide nanoparticles, and the drug doxorubicin. The final product combines double magnetic and molecular targeting to tumor tissues. Superparamagnetic Fe3O4 nanoparticles are first chemically deposited onto a surface of graphite oxide (GO) with the acquisition of a double GO@Fe3O4 composite. The material is then bound with the antitumor drug doxorubicin. The morphology, phase composition, and magnetic and optical properties of synthesized samples are characterized via thermal gravimetry, X-ray diffraction, magnetic susceptibility measurements, transmission electron microscopy, and via UV-visible and Raman spectroscopy. The optimal ratio of graphite oxide, iron oxide, and doxorubicin for the creation of a potential precursor of the new drug is established. The presence of doxorubicin and iron oxide in the composite is confirmed, making it possible to use an external magnetic field for targeted drug delivery towards the affected tissues. It is also shown that the composite retains its stability for a month in solutions with physiological pH values.

The effect of design parameters, electrical properties, and technological modes of formation on the efficiency of the photoelectrical conversion of solar cells with extremely thin absorbing layers based on the SnO2:F/TiO2/In2S3/In x Pb1 − x S/CuSCN is investigated. It is shown that both a decrease in resistance due to an increase in roughness and a decrease in the average grain size of the TiO2 films is attained with deposition using the sol-gel method under conditions of increased humidity. The use of Ni as the contact metal to a planarizing CuSCN layer provides the reduced value of the transient resistance. The optimization of the sequential resistance of the TiO2 film and contact resistance to the CuSCN layer provided an increase in the efficiency of photoelectric converters by a factor of more than four. The structures of solar cells formed in optimal technological modes showed the following characteristics: J sc = 9 mA/cm2, U oc = 720 mV, and they had an efficiency of 2.9%.

Polyelectrolyte and nanocomposite microcapsules with shells containing iron oxide (Fe3O4 magnetite) nanoparticles have been obtained using the layer-by-layer polyion assembly technique. The volume fraction of nanoparticles was varied by changing the number of their layers in the shell. The dependence of the microcapsule shell thickness on its structure, that is, on the total number of polyelectrolyte and magnetite nanoparticle layers, has been studied using atomic force microscopy. An increase in the number of polyelectrolyte layers in the shell structure leads to nonlinear growth of the shell thickness. Remote control over the permeability of microcapsules was achieved by their destruction under the action of an external acoustic (ultrasound) field. It has been established that the sensitivity of microcapsules to ultrasound depends on the volume fraction of magnetite nanoparticles in the shell. The ultrasonic treatment only produces breakage of the shells, without reducing their thickness and/or changing the composition. The results of this investigation can be used for to develop systems (in particular, magnetically sensitive) for targeted drug delivery and remote controlled release in the immediate vicinity of damaged cells and tissues in an organism.

The process of naphthalene adsorption from the gas phase by layers of core-shell polymer nanoparticles obtained with the use of molecular imprinting methods is studied by the fluorescent analysis method. Within the pseudo-second-order kinetic model of sorption, data on the rate constants of fluorescence change are obtained, primary regularities of the sorption process are determined, and the presence of selective recognition sites in the shells of nanoparticles is proven.

The unique physical and chemical properties of carbon nanotubes (CNTs), including SWCNTs (single-walled carbon nanotubes), allow their applications in many fields, including biomedicine. The optical properties of SWCNTs are attractive for application in the field of nanobiotechnology compared to MWCNTs (multi-walled carbon nanotubes). An important objective of SWCNT application for biomedical purposes is obtaining homogenous dispersions characterized by bioavailability and biocompatibility. The possibility of obtaining homogenous dispersions of different types of SWCNTs in biocompatible media for further use in different biomedical experiments and applications has been investigated. The sizes of SWCNT agglomerates in prepared dispersions were measured by the method of dynamic light scattering; bioavailability was studied by dark field microscopy in BEAS-2B bronchial epithelium cells. The dispersions were analyzed for the presence of bacterial contamination. Biocompatible and bioavailable dispersions have been obtained on the basis of cell culture media and 1% bovine serum albumin, which can be used in experiments on assessing the safety of SWCNTs at biological objects but have a number of limitations in the field of biomedicine. Dispergents based on lung surfactant components, which could be used in biomedical applications (DPPC and Survanta®), did not show efficency.

In this work, a novel approach to magnetic nanotheranostics based on the activation of magnetic nanoparticles (MNPs) with a nonheating low-frequency magnetic field has been described. Electromagnetic biomedical technologies implemented in low-frequency nonheating and radiofrequency heating magnetic fields have been briefly reviewed and compared. It has been shown that the activation of MNPs with nonheating magnetic fields has several advantages over activation with heating magnetic fields, namely, a more universal character and penetration ability into tissues, easy dosage and control, higher locality and safety, molecular selectivity, and lower cost. A combination of methods developed and patented by us can form a technological platform for new-generation low-frequency magnetic theranostics which is significantly more effective and possesses more options than conventional radiofrequency theranostics.

Functionalized magnetic nanoparticles (MNPs) controlled by an external magnetic field provide a new generation of promising nanobiomedical platform. Due to their ability to locally change the state of a biochemical system through two physical processes—thermal and nanomagnetomechanical—they are already used in experiments on targeted drug delivery and therapy of oncological diseases. This work considers the peculiarities, advantages, and drawbacks of each of these processes and the main parameters of the magnetic field controlling the MNP effect on different biomolecular targets. A brief review and comparative analysis of main experimental studies carried out in the scope of magnetic hyperthermia and nanomagnetomechanical actuation are carried out.

A study of the application of polyamic acids (PAA) and polyamidoimides (PAI) in manufacturing passivate and protective coatings for the crystal front facet of a semiconductor laser was carried out. The morphology of the surfaces of the deposited films was studied using atomic force microscopy. The structure of the deposited films and their roughness were examined. An analysis of the watt-ampere characteristics of the laser diodes showed that films based on polyamic acids markedly increase the magnitude of the peak power of semiconductor lasers. The highest value of the peak power was obtained for coatings based on polyamic acids instead of polyamidoimides. The value of the peak power for laser structures with a coating based on polyamic acids is 1.3 times higher than for structures without a polymer coating.