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Influence of freezing and thawing process on cryopreserved cells nuclei and surfaces. Functions and physico-chemical properties of cryoprotectants.
Golan, Martin ; Kratochvílová, Irena (advisor)
1 Abstract: Cryopreservation of cells is a complex process with many useful applications in basic biological research, medicine and agriculture. In this work we deepened the current understanding of the cryopreservation process both at physical and biological level. Results include characteristics of selected cryoprotectants (primarily DMSO, trehalose, antifreeze protein ApAFP752) in liquid phase, during phase transition and in solid phase, as well as their impact on cryopreserved cells states. Specifically, the level of cell viability, state of cell membrane and condition of cell nucleus (nuclear membrane, chromatin condensation, DNA strand breaks) are monitored over several time points after thawing. It is shown that S-phase cells (NHDF and MCF7 lines) suffer massive collapse of replication forks during cryopreservation which makes them much less suitable for cryopreservation than cells in other phases of the cell cycle. Several methods (most importantly Atomic Force Microscopy, Confocal Fluorescence Microscopy and Flow Cytometry) were used to examine the post-thaw state of cryopreserved cells. The acquired insights into cryodamage of cells can lead to optimization of current cryopreservation protocols and to more thorough evaluation of efficacy of future novel cryoprotectants.
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Influence of freezing and thawing process on cryopreserved cells nuclei and surfaces. Functions and physico-chemical properties of cryoprotectants.
Golan, Martin ; Kratochvílová, Irena (advisor) ; Raška, Milan (referee) ; Schneider, Bohdan (referee)
1 Abstract: Cryopreservation of cells is a complex process with many useful applications in basic biological research, medicine and agriculture. In this work we deepened the current understanding of the cryopreservation process both at physical and biological level. Results include characteristics of selected cryoprotectants (primarily DMSO, trehalose, antifreeze protein ApAFP752) in liquid phase, during phase transition and in solid phase, as well as their impact on cryopreserved cells states. Specifically, the level of cell viability, state of cell membrane and condition of cell nucleus (nuclear membrane, chromatin condensation, DNA strand breaks) are monitored over several time points after thawing. It is shown that S-phase cells (NHDF and MCF7 lines) suffer massive collapse of replication forks during cryopreservation which makes them much less suitable for cryopreservation than cells in other phases of the cell cycle. Several methods (most importantly Atomic Force Microscopy, Confocal Fluorescence Microscopy and Flow Cytometry) were used to examine the post-thaw state of cryopreserved cells. The acquired insights into cryodamage of cells can lead to optimization of current cryopreservation protocols and to more thorough evaluation of efficacy of future novel cryoprotectants.
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Preparing of the Chameleon coating by the Ion Jet Deposition method
Skocdopole, J. ; Aversa, L. ; Golan, Martin ; Schenk, A. ; Baldi, G. ; Kratochvílová, Irena ; Kalvoda, L. ; Nozar, P.
Preparation of chameleon coatings using an Ionized Jet Deposition (IJD) technique is reported in the present paper. IJD is a new flexible method for thin film deposition developed by Noivion, Srl. The chameleon coatings are thin films characterised by a distinct change of their tribological properties according to the external conditions. The deposited films of SiC and TiN materials were examined by the Raman spectroscopy, SEM and XPS. The results of the Raman spectroscopy have proved an amorphous structure of SiC films. The data from XPS on TiN films have shown that the\nfilms are heavily oxidized, but also prove that the films are composed of TiN and pure Ti. The SEM provided information about the size of grains and particles constituting the deposited films, which is important for tribological properties of the films. Deposition of the chameleon coating is very complex problem and IJD could be ideal method for preparation of this coating.\n
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Photogeneration of Charge Carriers in Organic Semiconductors
Heinrichová, Patricie ; Kratochvílová, Irena (referee) ; Cimrová,, Věra (referee) ; Weiter, Martin (advisor)
The interest in the detail knowledge about elementary electronic processes during photogeneration of charge carriers, which allow achieving higher efficiency of organic solar cells, grows with advent of the commercial organic solar cells production. The thesis is focused on study of photogeneration of charge carriers in organic semiconductors, especially in -conjugated polymer materials. First part of the thesis summarized state of the art in studies of photogeneration of charge carriers in polymer solar cells. Subsequent experimental and results part are focused on study of polymeric solar cells prepared from electron donor polymers MDMO-PPV, Tg-PPV, PCDTBT and PCBTDPP and electron acceptor derivates of fullerenes PC60BM and PC70BM. Results of the thesis are divided in tree main parts: 1) study of charge transfer between electron donor and electron acceptor materials by optical methods, 2) study of charge transfer between electron donor and electron acceptor materials by optoelectrical methods and 3) development of organic solar cells on flexible substrates. The last part is focused largely on deposition methods of active materials thin layer.
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Optoelectronic Properties of Organic Semiconductors
Navrátil, Jiří ; Boušek, Jaroslav (referee) ; Kratochvílová, Irena (referee) ; Weiter, Martin (advisor)
The main objective of this thesis is the study of the optical and optoelectronic properties of organic semiconducting materials. At the beginning of this thesis is shown the growing interest in these materials and their practical application. The theoretical part presents the current state of knowledge of studied problematic related to optical phenomena and the transport of charge carriers in organic semiconductors, photochormic phenomena of reversible molecular switch and charge transfer in DNA biopolymeric matrix. Experimental section, which consists of selected author’s publications, includes study of the charge transport, photochromic reversible switching and the role of dopant in pi-conjugated organic polymer system. Conductive and semiconductive characteristics of the DNA biopolymer have been aslo studied. Conductive and photoconductive techniques together with measurement of the optical characteristics have been used for organic semiconductors characterization.
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Sensoric Properties of Organic Materials
Tmejová, Kateřina ; Zmeškal, Oldřich (referee) ; Kratochvílová, Irena (referee) ; Nešpůrek, Stanislav (advisor)
The first part of the work is aimed to the study of changes of electrical properties of substituted phthalocyanines under the influence of humidity. Thin films were prepared by spin coating technique. During the influenece of humidity electrical conductivity increases. Sorption and desorption and the changes in electrical properties under the repated humidity exposure were investigated as well. Impedance spectroscopy was used for the studies. The second part of this work consists of optical studies and changes of optical parametrsunder the influence of different alcohols (methanol, ethanol, 2-propanol) exposures. The investigated samples were prepared by vacuum evaporation a glow-discharge-induced sublimation. The changes of optical reflectances of the films upon exposure to alcoholvapour-containg atmospheres were studied as a function of alcohol concetration and exposure time.
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Detection of Elliptical Particles in Atomic Force Microscopy Images
Sedlář, Jiří ; Zitová, Barbara ; Kopeček, Jaromír ; Todorciuc, T. ; Kratochvílová, Irena
In this paper we describe a method for detection and measurement of elliptical particles in atomic force microscopy (AFM) images. AFM imaging is used in physics to scan surfaces; the measured heights are represented by pixel values. Each sample in our project consisted of elliptical particles of principally the same size; the size could be characterized by the average length and width of a number of salient particles. The method we proposed is based on segmentation of undamaged particles and their approximation by ellipses; the major and minor axes provide robust estimates of the lengths and widths of the particles, respectively. The method is robust to distortions typical of AFM images. Its performance was demonstrated on images of pyrroles and compared with manual detection. Results show that the automatic method could be used in place of the time-consuming manual detection.
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Fluorescent nanodiamonds: The new platform for construction of chemo- and biosensors
Cígler, Petr ; Ledvina, Miroslav ; Tvrdoňová, Monika ; Řezáčová, V. ; Nesládek, M. ; Kratochvílová, Irena ; Fendrych, František ; Štursa, Jan ; Kučka, Jan ; Ráliš, Jan
Over the past few years, fluorescent nanodiamonds (FNDs) have been recognized as potential fluorophores for use in bioimaging, owing to their unique and attractive chemical and particularly spectral properties. The source material for their preparation, synthetic nanodiamond (ND), is non-expensive and commercially available. Notably, NDs have the highest biocompatibility of all carbon nanomaterials and their surface can be chemically modified by various techniques. FNDs are capable of fluorescing with almost quantitative quantum yields from point defects of crystall lattice - nitrogen-vacancy (NV) centers. In particular, the long-wavelength emission, high brightness, no photobleaching, no photoblinking, and an exceptional resistance to chemical degradation make them almost ideal core for development of fluorescent bioimaging probes.
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