National Repository of Grey Literature 17 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Study of isotopically labeled substances in living cells by means of Raman microscopy
Bura, Radek ; Mojzeš, Peter (advisor) ; Pilát, Zdeněk (referee)
Unicellular algae (microalgae) are able to produce a number of substances such as starches, oils, proteins, carotenoids, polyphosphates, or crystalline purines directly from inorganic sources by photosynthesis. Different species of microalgae can be used for the economic production of various biomolecules. Due to their autotrophic nature, microalgae are also unique as they can synthesize complex isotopically labeled biomolecules from simple isotopically labeled inorganic substances. Analysis of the chemical composition of microalgae by means of chemical-analytical methods is relatively complex, time-consuming, and laborious. Confocal Raman microscopy represents one of the optical methods by which the chemical composition of microalgae can be determined in situ, i.e. directly within intact cells. This technique combining confocal optical microscopy with Raman spectroscopy enables fast and non- destructive analysis of the chemical composition of substances in the investigated objects, including the effect of isotopic labeling. The chemical composition of the investigated objects is reflected by their Raman spectra, in the case of Raman mapping of microscopic objects by their chemical maps. In this work, a specific case of isotopic labeling was studied, namely the effect of heavy water (D2O) on the deuteration...
Optofluidic techniques for directed evolution of enzymes
Pilát, Zdeněk ; Ježek, Jan ; Samek, Ota ; Zemánek, Pavel ; Buryška, T. ; Damborský, J. ; Prokop, Z.
Enzymes are highly versatile and ubiquitous biological catalysts. They can greatly accelerate\nlarge variety of reactions, while ensuring appropriate catalytic activity and high selectivity.\nThese properties make enzymes attractive biocatalysts for a wide range of industrial and\nbiomedical applications. Over the last two decades, directed evolution of enzymes has\ntransformed the field of protein engineering.
Fluorescence and surface enhanced Raman spectroscopy in microfluidics for monitoring of enzymatic reactions
Pilát, Zdeněk ; Šmatlo, Filip ; Ježek, Jan ; Krátký, Stanislav ; Zemánek, Pavel
We have implemented two different systems for detecting the concentration of molecules in microfluidic systems. The first method uses optical fibers and detects the intensity of fluorescence, while the second method is using surface enhanced Raman spectroscopy (SERS).
Experimental fluorescence device for dielectrophoretic sorting of droplets in microfluidic chips
Ježek, Jan ; Pilát, Zdeněk ; Šmatlo, Filip ; Zemánek, Pavel
At present, many chemical and biological disciplines use different forms of spectroscopy for their observations. One of the most common methods is fluorescence spectroscopy. During the last seven years, microfluidic techniques began developing rapidly, using channels in which two immiscible liquids create droplets with diameters from units to tens to hundreds of micrometers. These droplets serve as liquid microcontainers containing the analysed sample and the necessary reagents. Using special microfluidic techniques, it is possible to fuse droplets with different contents (controlled triggering of chemical reactions), to change the concentration of reactants in the droplet with high speed (concentration gradients), or sort the droplets by content (creation of new cell strains).\n\n
Optical Micromanipulation Techniques Combined with Microspectroscopic Methods
Pilát, Zdeněk ; Prášil,, Ondřej (referee) ; Mojzeš, Peter (referee) ; Zemánek, Pavel (advisor)
Předložená dizertační práce se zabývá kombinací optických mikromanipulací s mikrospektroskopickými metodami. Využili jsme laserovou pinzetu pro transport a třídění živých mikroorganismů, například jednobuněčných řas, či kvasinek. Ramanovskou spektroskopií jsme analyzovali chemické složení jednotlivých buněk a tyto informace jsme využili k automatické selekci buněk s vybranými vlastnostmi. Zkombinovali jsme pulsní amplitudově modulovanou fluorescenční mikrospektroskopii, optické mikromanipulace a jiné techniky ke zmapování stresové odpovědi opticky zachycených buněk při různých časech působení, vlnových délkách a intenzitách chytacího laseru. Vyrobili jsme různé typy mikrofluidních čipů a zkonstruovali jsme Ramanovu pinzetu pro třídění mikro-objektů, především živých buněk, v mikrofluidním prostředí.
Optically trapped tunable droplet microlasers from liquid crystals
Pilát, Zdeněk ; Ježek, Jan ; Jonáš, A. ; Aas, M. ; Kiraz, A. ; Brzobohatý, Oto ; Zemánek, Pavel
We created a system for concurrent optical trapping, laser excitation and spectroscopy of liquid crystal droplets doped with a fluorescent dye. We observed whispering gallery modes and lasing of the droplet. We tuned the droplet laser frequency with optical forces, electric current or heating.
Compact device for fluorescence measurement by optical fiber in microfluidic chip
Ježek, Jan ; Pilát, Zdeněk ; Zemánek, Pavel
In our paper we present a device that combines fluorescence spectroscopy with fiber optics. The device allows high speed detection (in the order of kHz) of the fluorescence signal, which is coming from the sample by an inserted optical fiber, e.g. from a micro-droplet flow in a microfluidic chip, from the liquid flowing in the transparent capillary, etc. The device uses a laser diode at a wavelength suitable for excitation of fluorescence, excitation and emission filters, optics for focusing the laser radiation into the optical fiber, and a highly sensitive fast photodiode for detection of fluorescence.
Raman tweezers in microfluidic systems for automatic analysis and sorting of living cells
Pilát, Zdeněk
We have devised an automatic analytical and sorting system combining optical trapping with Raman spectroscopy in microfluidic environment, together with computerized real time image analysis, spectra processing and micromanipulation. This device serves to identify and sort biological objects, such as living cells of various prokaryotic and eukaryotic organisms based on their Raman spectral properties. This approach allowed us to collect information about the chemical composition of the objects, such as the presence and composition of lipids, proteins, or nucleic acids without using artificial chemical probes such as fluorescent markers. The non-destructive and non-contact nature of this optical analysis and manipulation allowed us to separate individual living cells of our interest in a sterile environment and provided the possibility to cultivate the selected cells for further experiments. The special microfluidic chip uses gravity to move the cells across the sorting area. Our system uses dedicated software to achieve fully automated spectral analysis and sorting. The devised system is a robust and universal platform for non-contact sorting of microobjects based on their chemical properties. It could find its use in many medical, biotechnological, and biological applications.
Raman tweezers for sorting of living cells
Pilát, Zdeněk ; Ježek, Jan ; Kaňka, Jan ; Šerý, Mojmír ; Jákl, Petr ; Zemánek, Pavel
We have developed an instrument for automatized analysis and sorting of living cells of unicellular algae and other micro-objects based on laser tweezers and Raman spectroscopy. The system comprises the Raman tweezers setup, special microfluidic chip, and a specialized software allowing image recognition, spectral analysis, and automated sorting functions. The resulting instrument allows non-destructive analysis of chemical properties of living cells and their automatic separation for further examination or cultivation.

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