[Methods for Reducing Laser Speckles to Achieve Even Illumination of the Microscope Field of View in Biophysical Studies].

The aim of this work was to compare different speckle reduction techniques. It was shown that the use of devices based on liquid crystals only leads to partial reduction of speckle contrast. In quantitative luminescent microscopy an application of the mechanical devices when a laser beam is spread within the field of view turned out to be more efficient. Laser speckle noise was virtually eliminated with the developed and manufactured mechanical device comprising a fiber optic ring light guide and the vibrator that permits movement of optical fiber ends towards the laser diode during measurements. The method developed for the analysis of microarrays was successfully applied to the problem of speckle reduction.

[Method for automated extraction and purification of nucleic acids and its implementation in microfluidic system].

A method and a microfluidic device for automated extraction and purification of nucleic acids from biological samples have been developed. The method involves disruption of bacterial cells and/or viral particles by combining enzymatic and chemical lysis procedures followed by solid-phase sorbent extraction and purification of nucleic acids. The procedure is carried out in an automated mode in a microfluidic module isolated from the outside environment, which minimizes contact of the researcher with potentially infectious samples and, consequently, decreases the risk of laboratory-acquired infections. The module includes reservoirs with lyophilized components for lysis and washing buffers; a microcolumn with a solid-phase sorbent; reservoirs containing water, ethanol, and water-ethanol buffer solutions for dissolving freeze-dried buffer components, rinsing the microcolumn, and eluting of nucleic acids; and microchannels and valves needed for directing fluids inside the module. The microfluidic module is placed into the control unit that delivers pressure, heats, mixes reagents, and flows solutions within the microfluidic module. The microfluidic system performs extraction and purification of nucleic acids with high efficiency in 40 min, and nucleic acids extracted can be directly used in PCR reaction and microarray assays.