The increase of the sensitivity of surface plasmon resonance (SPR) refractometers was studied experimentally by forming a periodic relief in the form of a grating with submicron period on the surface of the Au-coated chip. Periodic reliefs of different depths and spatial frequency were formed on the Au film surface using interference lithography and vacuum chalcogenide photoresists. Spatial frequencies of the grating were selected close to the conditions of Bragg reflection of plasmons for the working wavelength of the SPR refractometer and the used environment (solution of glycerol in water). It was found that the degree of refractometer sensitivity enhancement and the value of the interval of environment refractive index variation, Δn, in which this enhancement is observed, depend on the depth of the grating relief. By increasing the depth of relief from 13.5 ± 2 nm to 21.0 ± 2 nm, Δn decreased from 0.009 to 0.0031, whereas sensitivity increased from 110 deg./RIU (refractive index unit) for a standard chip up to 264 and 484 deg./RIU for the nanostructured chips, respectively. Finally, it was shown that the working range of the sensor can be adjusted to the refractive index of the studied environment by changing the spatial frequency of the grating, by modification of the chip surface or by rotation of the chip.

Abstract. The influence of the sensitive element fabrication technology and noise performance of surface plasmon resonance (SPR) immunosensor on sensitivity and stability of operation inherent to the "Plasmon" series instrument has been investigated to improve reliability of diagnosis and treatment of the Epstein-Barr herpes virus disease. To minimize the effect of the temperature change induced noise, compensation (introduction of the reference channel) and stabilization (active thermal control) methods were applied, allowing to substantially enhance resolution of the used SPR sensor system.

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Mechanism of tumor progression in malignant gliomas and other tumors of the body were studied to identify the main pathogenetic link. Indicators of the charge of cell membranes, including the membranes of blood cells, can be considered in vein. These indicators are universal for any type of tumors, and not tissue-specific. Indicators of many significant processes in the body depend on the level of cellular charge, which emphasizes its dominant role. Interaction of reparative processes of inflammatory genesis with regenerative processes carried out by blood stem cell in relevant studies and in this study by mesenchymal blood stem cells. The interaction is under the control of the epidermalmesenchymal transition depends on a large extent on the cellular charge of blood cell membranes. The paper presents the correlation features between the pools of cells of inflammatory and regenerative origin (leukocytes, lymphocytes, granulocytes, and monocytes), the charges of their membranes in gliomas of III grade of malignancy and meningiomas of I grade of malignancy studied in vitro. Membrane charges were determined indirectly, through the level of aggregation of blood cells, using the surface plasmon resonance method where the aggregation expressed in arbitrary SPR units. To detect a latent correlation, low concentrations of verapamil hydrochloride (10,000-fold dilution) were added to the blood samples before determining the level of cell aggregation and the samples were exposed to low-level laser radiation with an oscillation frequency of 1.2 Hz. Results indicate the great importance of maintaining a normal, rather than reduced, level of cell membrane charge.

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