Summary. Aim: To assess oxidative stress and structural changes of the serum albumin in rats with transplanted Walker-256 carcinosarcoma (W256) strains with varying sensitivity to doxorubicin (Dox). Materials and Methods: The study was performed on female Wistar rats with transplanted W256. On the 9th day after tumor cell transplantation an analysis of peripheral blood, oxidative stress para­meters, and structural changes of serum albumin of experimental animals was performed. Results: On the 9th day after W256 transplantation a significant increase in the leukocyte counts was observed in the groups of animals with the Dox-resistant and parental (Dox-sensitive) W256 tumors compared with the group of the intact animals: up to 14.24 ± 1.92 • 103/μl and 9.78 ± 1.03 • 103/μl, vs 8.92 ± 1.04 • 103/μl, respectively, due to the increase of granulocyte and monocyte counts. The number of lymphocytes was within the normal range. The level of hemoglobin and the erythrocyte counts were also within normal limits, but hematocrit in both groups of animals with tumors somewhat increased against the background of 1.2-fold elevation of the mean erythrocyte volume. In the group of rats with Dox-resistant W256, there was observed a decrease in the plateletcrit by almost 22% and thrombocyte counts — by 28%. Analysis of oxidative stress indices revealed a significant increase in the level of reactive oxygen species, 2-fold increase of malonic dialdehyde level and the degree of oxidative damage of blood plasma proteins, as well as a decrease in the activity of catalase in hemolysates (by 12–15%) in both groups of tumor-bearing rats. With the use of differential scanning calorimetry, UV and fluorescence spectroscopy we have revealed anomalous conformational changes of albumin caused by tumor development: structural rearrangements in the region of its first drug binding site located in the IIA domain, separation of globular parts of albumin molecule, and partial “opening” in a protein molecular three-domain structure resulting a loss of its thermal resistance. Conclusion: The development of transplanted Walker-256 carcinosarcoma, especially its Dox-resistant variant, results in severe metabolic intoxication reflected in alteration of hematological parameters, and indices of oxidative stress, as well as architectonic changes of serum albumin.

Photosensitive plasmon-active structures derived from nanostructured gold films and chalcogenide glass As20Se80 have been prepared. Regular sub-wavelength reliefs are formed on the surface of As20Se80 glass due to the interaction of an amorphous chalcogenide glass film located on the metallic film nanostructures of different geometry and a localized near-field generated by photoexcitation of surface plasmon resonance in the gold films. The shape of the reliefs depends on the polarization of the laser light beam.

Combined mechanical scanning probe lithography (SPL) approach applied for the direct mask-less modification of graphene oxide (GO) flakes and the mask patterns engraving in layers of chalcogenide resist with a nanometer scale resolution have been implemented in this work. It was compared the dynamics of mechanical modification of chalcogenide films and multilayer GO flakes deposited from an aqueous suspension. The double-layer As40Se60/As4Ge30S66 chalcogenide resist developed for mechanical SPL and pattern formation processes have optimized The resist with the thickness close to 100 nm provides formation of minimal pattern elements with the size of several tens nanometers. The SPL approach was realized on the basis of serial NanoScope IIIa Dimension 3000 (TM) scanning probe microscope, and original software utilities were developed. These mechanical SPL could be intended for the verification of innovative ideas in academic researches, the laboratory-level device prototyping, developing the functional prototypes of new devices in bio/nanosensorics, plasmonics, 2D electronics and other modern technology branches.

This work provides a review of commonly used approaches for fine manipulations with nanoobjects by means of scanning probe microscopes and describes an original alternative cost-effective nanomanipulation method. High precision manipulations are important for up-to-date technologies of nanoelectronic, molecular, hybrid and nanomechanical devices and sensor systems especially for the state of the art fundamental and applied researches. A new method to form nanoassemblies by using asymmetric nanoparticles fixed on the surface with the viscoelastic linker has been proposed, theoretically substantiated and experimentally realized. An original theoretical model has been proposed to describe the ordering process of the linked nanorods by means of the multipass interaction with an atomic force microscope (AFM) tip.In addition, an adjustment of the tip-surface interaction has been proposed and implemented which is independent of the AFM. This original approach is based on additional ultrasonic excitation of the surface. This also enabled us to control the degree binding of the nanoparticles with the substrate.With these techniques we were able to form sets of chains (more than 5-μm length) consisting of nanometer-sized (10x50 nm) gold nanorods (NRs) linked to the surface of gallium arsenide by an organic linker. It has been shown that the viscoelastic binding of asymmetric nanoparticles to the surface allows us to create linear assemblies of nanoobjects in just a few passes of the AFM probe.The proposed technique significantly increases manufacturability of nanomanipulations. Direct formation of nanostructures can significantly reduce the cost of their formation in comparison with modern conventional technological approaches, which in many cases may even have some fundamental limitations (in resolution, in materials used, etc.).

In this paper, the features of the microstructure of magnetic domains observed in ferrite-garnet films (FGF) have been presented. The studied FGF with orientation (111) were grown on gallium-gadolinium substrate by using liquid-phase epitaxy. The study of distribution inherent to magnetic domains was carried out using magnetic force microscopy (MFM) with the scanning probe microscope NanoScope IIIa Dimension 3000. In the course of these researches, optimization of the MFM method was carried out to obtain high-quality and correct images of magnetic domains in FGF. Nanorelief and magnetic microstructure of FGF surface were studied, depending on their thickness, on external magnetic field and doses of boron ion implantation. For these objects, it was established that stripe domain structure is characteristic, the period of which depends on the film thickness. The nature of transformation of domain structure depending on thickness is close to that theoretically predictable at low thicknesses (up to 10 μm). Nanorelief of film surfaces is virtually unchanged depending on thickness. An external magnetic field with the magnitude 4 mT causes significant changes in domain configuration and allows to visualize heterogeneity of magnetic structure. Ion implantation leads to a slight smoothing of nanorelief films (roughness of 0.2 nm) and to more accurate displaying the magnetic microstructure, which is associated with processes of structural ordering under ionic bombardment.

AIM:To synthesize and to study for photodynamic activity a composite photosensitizer consisting of chlorin e6 and human serum albumin nanoparticles (HSA NPs).MATERIALS AND METHODS:Starting from sorption-purified HSA, the albumin nanoparticles with a different degree of lysine residues cross-linking (10; 20; 40, and 100%) were obtained by the coacervation method. The HSA NPs were used for synthesis of nanocomposites with chlorin e6 and fluorescein isothiocyanate (FITC)-labeled preparations. Malignant lymphocytes of the MT-4 (human T-cell leukemia) line and normal lymphocytes of healthy donors served as cell targets. For photodynamic treatment, a semiconductor laser was exploited as a light source, and cell viability was assessed by MTT or trypan blue dye exclusion tests. For cell imaging and HSA NPs visualization, the fluorescence microscopy and transmission electron microscopy were applied, respectively. C57Bl/6 mice were used in animal experiments.RESULTS:The absorption and fluorescence spectra of chlorin e6-HSA NPs composites were characterized, and by the electron microscopy investigation the size of NPs (nanospheres) was estimated: 100-120 nm. FITC-labeled albumin preparations allowed to establish that HSA NPs have much higher exposition and concentration dependent affinity to malignant cell surface than initial HSA. In experiments with MT-4 cells on PDT activity of chlorin e6-HSA NPs, the nanocomposite effectiveness elevated along with increasing percentage of cross-linked amino acid residues, and for the nanocomposite with 100% of albumin cross-linking it exceeded the activity of free chlorin e6. In contrast to malignant cells, the complexation of chlorin e6 with HSA NPs decreased its photodynamic effect on normal human lymphocytes. Intravenous introduction of the chlorin e6-HSA NPs composite to mice showed prolonged circulation of the nanocomposite in blood in comparison with free PS.CONCLUSION:Promising results obtained with chlorin e6-HSA NPs composites warrant conduction of full-fledged PDT studies in vivo using the nanocomposites as photosensitizers.

We have established that mass-transport processes in two types of amorphous materials, based on light-sensitive inorganic compounds like Se and As20Se80 chalcogenide glasses (ChG), can be enhanced at the nanoscale in the presence of localized plasmonic fields generated by visible light in gold nanoparticles (GNPs), if the condition of surface plasmon resonance (SPR) is fulfilled. It was found that irradiation by light in the presence of SPR produces profound surface nanostructurizations, and variation in topography follows closely and permanently the underlying near field intensity pattern. We have proposed a model of mass-transport in which the existence of moving anisotropic dipolar units and internal electric field in ChG as a main driving force of this movement is suggested.

UNLABELLEDIn research of the last decade, rhythmic (circadian) variations of vascular endothelial growth factor (VEGF) production by tumors were discovered. The present paper authors have earlier synthesized and characterized a new derivative photosensitizer - an immunoconjugate of hematoporphyrin with antiVEGF antibodies.AIMTo elaborate and to test a novel modification of the photodynamic therapy of tumors (PDT) method, founding upon a timed introduction of the immunoconjugated photosensitizer to tumor-bearing animals, so that this coincides with a maximum content of VEGF in tumor tissues.METHODSCircadian variations of VEGF contents in murine transplanted tumors, Lewis lung carcinoma and sarcoma 180, were determined by ELISA method. Immunoconjugated photosensitizer concentrations in tumors were estimated by spectrofluorometry. Photoirradiation of the tumors was carried out with a red light (wavelength of 635 nm) from a semiconductor laser. Light doses were chosen, calculating on a partial inhibition of tumor growth, in order that a dependence of PDT efficiency on a daily time-moment (circadian rhythm phase) of the treatment could be observed distinctly.RESULTSCircadian variations of the VEGF levels in Lewis lung carcinoma and sarcoma 180 were demonstrated with the maximum at 14:00 h and the minimum at 02:00 h. Intra-abdominal introduction into tumor-bearing mice of the immunoconjugated photosensitizer resulted in a greater accumulation of the immunoconjugate in tumors at 14:00 h than at 02:00 h. Laser irradiation of carcinomas and sarcomas at 14:00 h or 02:00 h after introduction of the immunoconjugated photosensitizer to mice the day before at the same time points, induced a significantly enhanced inhibition of tumor growth in animals treated at day-time versus those treated at night-time.CONCLUSIONThe obtained results justify further attempts to transfer principles of tumor chronochemotherapy onto photodynamic therapy.

The paper presents a study on modeling the mechanical interaction between the tip of a scanning atomic force microscope (AFM) and surfaces of various types, which makes it possible to optimize parameters and modes for mechanical AFM nanolithography. The practical assessment of mechanical nanoprobe lithography based on the method of a direct surface patterning was carried out during fabrication of functional elements for molecular electronics. Polymethine dye nanowires of a specified configuration and the cross-section 3×20 nm have been successfully formed in a multilayer polytetrafluoroethylene/gold/silicon nanostructure.

Transistor heterostructures with high-carrier-mobility have been studied. It is shown that, as the γ-irradiation dose Φ increases, their degradation occurs in the following sequence. (i) At Φ < 10 7 rad, the GaAs surface layer is damaged to a depth of 10 nm due to a >0.2-eV decrease in the diffusion energy of intrinsic defects and, probably, atmospheric oxygen. (ii) At Φ > 10 7 rad, highly structurally disordered regions larger than 1 μm are formed near microscopic defects or dislocations. (iii) At Φ > 10 8 rad, there occurs degradation of the internal AlGaAs/InGaAs/GaAs interfaces and the working channel. An effective method for studying the degradation processes in heterostructures is to employ a set of structural diagnostic methods to analyze processes of radiation-induced and aging degradation, in combination with theoretical simulation of the occurring processes.

The measurements of capillary forces on different diamond-like materials and carbon allotropic modifications taken using a scanning force microscope have been discussed. The amplitude-frequency characteristics of the nanorelief surfaces studied have been widely varied by plasma chemical treatments. The measurements of capillary forces have been compared with the macroscopic values of a wetting angle. It has been shown that a macroscopic wetting angle depends on the averaged surface energy only and is slightly dependent on the nanorelief characteristics, and nanocapillary forces correlate with both surface relief parameters and the local angle of wetting. Criteria for multimeniscus mode of capillary forces measurement in the surface force spectroscopy and the prospects of this procedure application for mapping the real surface energy have been considered in detail.

The paper presents an overview and analysis of the most reliable and at the same time rather simple theoretical models describing liquid nanomeniscus geometry and forces occurring between atomic force microscope (AFM) probe and a real surface.There are experimental results in capillary bridge force rupture measured in air, and interaction force under water buffer obtained over surfaces of different nature.It is shown that the theoretical models quite adequately describe the processes observed experimentally and, in particular, bridge ruptures dynamics at the vertical probe withdraw for different speeds.Discussed here are some methodological peculiarities and nanocapillary force spectroscopy diagnostic capabilities for surface energy mapping, prospects of using of a liquid nanomeniscus in local nanochemistry, nanolithography and nano-electrochemistry of a surface.

Demonstrated experimentally in this work was the possibility of controlled handling the nanoparticles with the size from 50 up to 250 nm on a semiconductor surface by using an atomic force microscope under conditions of acoustic excitation. It has been shown that the selective transport of particles of a certain size is possible owing to the change of an ultrasonic vibration amplitude. Also in this study, possible mechanisms in which ultrasound may influence the particle-surface interaction and the probe-particle (surface) interaction have been analyzed.

An influence of the randomly distributed defects (RDD) in the bulk crystal on value of the intensities of hkl and (hkl) over bar Laue-reflections' ratio, Y = Ihkl/I((hkl) over bar) is revealed. It has been shown the possibility to carry out the RDD-parameters diagnostics by deviation of Y for crystal with RDD from Y(perf) for perfect crystal as well as by its variation with the crystal thickness, both for radiation wavelengths above and below the absorption K-edge. By analogy, for the crystal with RDD, due to the diffuse-scattering component contribution, the value of the parameter Y(S) for the intensities jump near the absorption K-edge is decreased, and just by both this decreasing degree and its dependence on the crystal thickness, the RDD characteristics can be determined as well.

This paper reports the coefficients CAB for the k-linear term in dispersion relation E(k) for holes of the upper valence bands Gamma(-)(6) and Gamma(+)(7) in p-CuInSe2 crystals. We also obtained the tensor components for the carrier effective masses m(perpendicular to,parallel to)( A,B,C) in all three valence sub-bands of the model semiconductor. It was shown that the energy spectrum parameters for holes in CuInSe2 allow successful explanation for the anisotropy of tensor components describing the interband light absorption coefficient and the published data for the temperature variation of the Hall coefficient, total Hall mobility and thermal voltage within the temperature range 100 K <= T <= 350 K.

The method for determination of the single-crystal defects' parameters is proposed and experimentally certified. This method is based on the joint analysis of deformation dependences (DD) of the total integrated reflective power (TIRP), which are obtained within the approximations of 'thin' and 'thick' crystals in the Laue geometry. The semi-phenomenological models of the TIRP DD, which have been developed by authors within the scope of the dynamical x-ray scattering theory [1, 2], are used and improved. The physical nature of proposed-method high information capability is revealed.

Silicon-based nanotechnology is highly promising since it is compatible with conventional silicon integrated technique. To date silicon nanowires have been synthesized by varying experimental conditions and a wide range of electronic nanodevices have been demonstrated. A key challenge facing the device realization is the elaboration of a self-assembly nanotechnology enabling the formation of nanoobjects with preset shape and size, crystalline structure, chemical composition, and consequently, physical and chemical properties. To integrate nanodevices into conventional silicon chips, a spatial location and density distribution of nanowires on a chip should be controlled as well. To locate nanowires on desired places with a specific distribution, one should commonly use nanolithography. In this paper we describe a new possibility and its practical realization on silicon for metal-enhanced growth of nanowires with a self-arrangement over the substrate. The proposed physical and mathematical models of the effect is a thermo-stimulated analogue of Liesegang pattern theory. Results of the modeling fit satisfactorily a geometry and nanowire size distribution inside the structure.

Within the scope of the dynamical theory of x-ray scattering in crystals with defects of arbitrary sizes for Laue diffraction geometry, the phenomenon model is developed for the total integrated reflective power (TIRP) dependence for 'thin' crystals, which contain defects, on the cylindrical elastic bent degree. Those parameters of this model, which describe the TIRP deformation dependence, are independent on the investigated single-crystal defect structure, but are determined only by the diffraction conditions. However, they proved to be different for the TIRP Bragg and diffuse components. Within the frameworks of the proposed approach, the defect-structure diagnostics of the CZ Si single crystals, which have been annealed at 1080 degrees C during 2, 6 and 8 h, is carried out by the TIRP deformation dependences. The radii and concentrations of defects, which are simultaneously present in crystals, are determined without any artificial limits on its sizes.