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Microfluidics
Abrahám, Martin ; Sluše, Jan (referee) ; Rudolf, Pavel (advisor)
The bachelor's thesis deals with phenomenon of gas and fluid flow in equipment with micro scale. The first part is dedicated to describe Reynolds number and laminar flow in micro channel. The second part is dedicated to describe specific equipment for pumping a working material – micropumps, microvalves, microneedels, micromixers.
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Application of pressurized hot water for etching of microfluidics
Vašina, M. ; Grym, Jakub ; Foret, František
The subject of this study is a new method of glass etching and its application in microfluidics. Commonly, hydrofluoric acid is used for glass etching. In this study we have tested a new method of glass etching using pressurized hot water. Test motives were prepared using photolitography and metal sputtering on the glass substrate and the etching was performed in a newly developed device capable to compress and heat water to its critical point. Electron microscopy and profilometry have been used for analyzing the surface of the etched glass substrate.
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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.
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Fabrication of 3D diamond membranes for microfluidic systems
Varga, Marián ; Babchenko, Oleg ; Bauerová, Pavla ; Hruška, Karel ; Jurka, Vlastimil ; Kromka, Alexander ; Rezek, Bohuslav
Perfusion of cell medium, especially in microfluidic devices, can provide in-vivo-like conditions for cell cultures. The most recent demand on such systems is to include electronically active artificial cell support for in-situ monitoring. Diamond thin films exhibit advantageous combination of physical, mechanical, chemical, biocompatible and electronic properties for this purpose. In this work we explore two strategies for fabrication of self-standing three-dimensional nanocrystalline diamond membrane for implementation in microfluidic invivo like experiments: i) nucleation and chemical vapour deposition (CVD) growth of diamond on porous 3D carbon foam (with 80 pores per inch) and ii) selective diamond growth predefined by photolithographic processing using copper grid mask. The morphology and material quality of the fabricated membranes are characterized by scanning electron microscopy and Raman spectroscopy.
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Microfluidics in search for catalysts for biomass conversion into liquid fuels
Tesař, Václav
Paper surveys recent developments of combinatorial chemistry characterised by testing many substances and their mixtures simultaneously. Attention focuses on the progress made possible by applying small-scale no-moving-parts fluidics. Encountered problems like small Re and their solutions are demonstrated on author's development of a microfluidic unit for parallel testing of catalysts improving effectiveness of Fischer-Tropsch synthesis of liquid fuels from biomass.
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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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Fluidics: what it is, where it is heading - and how it will change the world we line in
Tesař, Václav
Fluidics, technique of handling fluids, is usually meant to imply absence of moving components. It is less known and used than it deserves considering the advantages it offers. Recently its applications became more widespread thanks to two development directions. On one hand, it is the power fluidics, handling larger flow rates. Newly developed are no-moving-part fluidic pumps for dangerous liquids (in particular radioactive ones) — and fluidic oscillators for generation of microbubbles used in waste water processing and growth of unicellular plants. The other rapidly growing development direction is microfluidics, often integral with electronic circuitry on the same substrate. It has immense possibilities in sensors and also in handling small amounts of fluids e.g. in microchemistry.
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Biosensors for Environmental Monitoring and Biomedical Applications
ŠTOFIK, Marcel
Study of biosensors has become an essential part of research in biotechnology. Biosensors as fast, portable, highly sensitive, and low-cost bioanalytical detection devices have been utilized in many fields of human activity. The first part of the presented work focuses on electrochemical biosensors for rapid environmental screening of herbicides as water pollutants. A sol-gel immobilization method for a photosystem II (PSII) complex is studied in order to enhance the sensitivity and the signal strength and stability of a PSII-based biosensor. Computer simulations of a PSII biosensor are employed with the aim to find out how the immobilization membrane properties influence the biosensor parameters. Newly developed immobilization by a thin-layer membrane based on the results of computer simulations and revised measurement protocols are presented. The second part of the work is devoted to synthesis and electrochemical detection of newly developed metal labels for electrochemical immunosensors. The synthesis of dendrimer-encapsulated silver nanoparticles and biorecognition properties of biotin-nanocomposite conjugates are discussed. For detection of synthesized labels, a microfluidic detector was manufactured and tested and different approaches to packing of a microfluidic chip employing polydimethylsiloxane (PDMS) were investigated. Newly designed microstructures for a microfluidic separator of magnetic beads (MBs) were studied by computer simulations. The separator was made and trapping of MBs for the further employment in MBs-based immunoassays are presented
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Mikrofluidika v řízení živých tvorů
Tesař, Václav
Microfluidics had recently interesting uses in biomedical sciences. Its development towards smaller scales has reached the stage making possible an interfacing with the brain cortex at the cellular level: reading and inputting the neural signals. The signals and their processing are mostly of electronic character, but fluidics plays in this application one of the key supporting roles. The contribution on the one hand lists therapeutical applications, but on the other hand notes current trend of military uses of insects or small rodents who can intrude into military establishments and gather there pictorial information.
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Víceúrovňové větvení průtoku
Tesař, Václav
Paper presents basic concepts governing distribution of a fluid flow into a large number of parallel microdevices. Laws for multi-level progressive division into branches are first validated by comparison with known data on mammalian respiratory and cardiovascular systems. Then the optimality criterion is sought for the specific conditions of channels etched in planar substrates.
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