Národní úložiště šedé literatury Nalezeno 28 záznamů.  1 - 10dalšíkonec  přejít na záznam: Hledání trvalo 0.21 vteřin. 
Epitachophoretic separation and concentration of large volume samples
Voráčová, Ivona ; Foret, František ; Datinská, Vladimíra ; Novotný, Jakub ; Gheibi, P. ; Berka, J. ; Astier, Y.
There has been a growing interest in developing isotachophoretic protocols for concentration and purification of DNA as an alternative to the solid phase extraction protocols of DNA preparation. Also concentration of DNA from large volume samples is required. We have developed a new device suitable for separation, concentration and collection of ions from several milliliter sample volumes into microliter fractions. We have used a discontinuous electrolyte system comprising of the leading and terminating electrolytes utilized for concentration of samples containing DNA fragments. The method is simple, fast with high concentration factor and without extensive surface interactions.
Hexahistidine-based tag for capillary electrophoresis-mass spektrometry analysis of oligosaccharides and N-linked glycans
Partyka, Jan ; Křenková, Jana ; Čmelík, Richard ; Foret, František
Various basic amino acids and peptides were studied as an alternative labels for capillary electrophoresis-mass spectrometry analysis of oligosaccharides. The hexahistidine-based label with big number of positive charges allowed to use effective and sensitive CE-MS analysis in positive ion mode both neutral and acidic glycans.
Microfluidic device for cell counting and electrical lysis
Václavek, Tomáš ; Křenková, Jana ; Foret, František
This lecture presents two microfluidic devices as essential units for single cell proteomic analysis, firstly a device for cell counting based on resistive pulse sensing as an alternative to optical platforms based on visual control over the sample input, secondly a unit for electrical lysis of cells using direct current voltage pulses to lyse cells one by one with a possibility to analyze the distinct lysate zones by electrospray ionization mass spectrometry.
Photon-upconverting nanoparticles as a novel background-free label in immunoassays
Farka, Z. ; Hlaváček, Antonín ; Mickert, M. J. ; Skládal, P. ; Gorris, H. H.
Photon-upconverting nanoparticles (UCNPs) have become an attractive label in immunoassays because their anti-Stokes luminescence can be excited by the NIR laser and detected in the VIS region without optical background interference. Further advantages of UCNPs include good photostability, large anti-Stokes shifts, and multiple narrow emission bands that can be used for multiplexed detection. We have developed a competitive upconversion-linked immunosorbent assay (ULISA) for detection of the pharmaceutical diclofenac (DCF) in surface waters. Silica-coated UCNPs (50 nm in diameter) with carboxyl groups on the surface were synthesized and conjugated with the secondary anti-IgG antibody. The structure and monodispersity of the nanoconjugates was studied by TEM and agarose gel electrophoresis. Using a highly affine anti-DCF primary antibody, the optimized ULISA provided a detection limit of 50 pg·mL−1.
Characterization of upconversion nanoparticles by fluorescence spectrometry and capillary electrophoresis
Vaněčková, T. ; Zítka, J. ; Hlaváček, Antonín ; Adam, V. ; Vaculovičová, M.
Upconversion nanoparticles (UCNPs) are a novel class of luminescent tags for applications in life and material sciences. Unlike traditional fluorophores, UCNPs exhibit emission of shorter wavelength under near-infrared excitation (typically 980 nm). In this work, we have examined these unique photophysical properties by fluorescence spectrometry and capillary electrophoresis. UCNPs co-doped with Yb(III) and Er(III) were characterized using laboratory-made fluorescence spectrometer. We have exploited and evaluated two excitation sources and the dependence of the fluorescence of UCNPs on the relative excitation power. Moreover, capillary electrophoresis with laser-induced fluorescence (CE-LIF) detection was for the first time used for characterization of the nanoparticles. It was proved that CE-LIF is a valuable method to be used for investigation of upconversion luminiscence and monitoring of the interactions of UCNPs with other molecules of interest.
Hexahistidine labeling of oligosaccharides
Partyka, Jan ; Křenková, Jana ; Foret, František
We have presented another approach for labeling of oligosaccharides suitable for\ncapillary zone electrophoresis coupled with mass spectrometric detection.\nOligosaccharides labeled by peptides with hexahistidine sequence have faster\nseparation resulting in two or three times shorter time in comparison to oligosaccharides\nwith singly charged labels.
Development of microfluidic device for droplet generation and microparticle encapsulation
Křivánková, Jana ; Foret, František
Microfluidic devices combined with various bioanalytical and optical sensors proved\ntheir potential in chemical, biological, and biomedicine applications. At a droplet\nmicrofluidic device a fluid is divided into numerous droplets surrounded by a\ncontinuous immiscible fluid phase. Generated droplets serve then as\nvessels/microcapsules for delivering drugs, nutrients as well as for encapsulating of\nbiologically active particles and cells.\nDescribed experimental study deals with the development of a practical dropletbased\nmicrofluidic chip useful for production of monodisperse water/oil emulsion and\nfor encapsulation of thin-metal magnetic microsheets.
Microfluidic device for cell counting and characterization
Václavek, Tomáš ; Křenková, Jana ; Foret, František
Integration of cell counting unit is an important step in developing of microfluidic\ndevice for cellular analysis. Here we present a microfluidic device for cell counting\nbased on resistive pulse sensing.
CE-nESI/MS in electrode-free design: narrowing the separation channel to 5 μm
Týčová, Anna ; Foret, František
Capillary electrophoresis-nanospray/mass spectrometry (CE-nESI/MS) in electrodefree\narrangement represents a very simple instrumentation for analysis of biomolecules.\nSo far, CE-nESI/MS analyses in this design were limited to 10-75 μm ID of the\nseparation channel. Although the work with narrower dimensions brings several\nchallenges, there is a great potential for better sensitivity, improved separation power\nand lower sample consumption. This work is devoted to some practical aspects of\nexperiments in narrow bore channels and systematic evaluation of CE-nESI/MS\nanalyses conducted in capillaries of 25, 15 and 5 μm ID.
A novel nanospray liquid junction interface for versatile CE-MS
Křenková, Jana ; Haselberg, R. ; Somsen, G. W. ; Foret, František
In this work we present a new polyimide-based liquid junction nanospray interface, combining the advantages of sheath flow and sheathless designs. The liquid junction interface was prepared as a hybrid microfabricated plastic liquid junction sprayer allowing to perform analysis in standard (30-100 micro m ID) separation capillaries. The interface incorporates a self-aligning port for coupling of the separation capillary as well as ports for automated flushing of both the liquid junction and the separation capillary. The interface permits performing CE both with and without electroosmotic flow. The use of large bore capillaries allows injection and preconcentration of larger sample volumes, favoring detection sensitivity. Different compositions of the spray liquid and BGE can be used when needed.

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