National Repository of Grey Literature 15 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Drop coating deposition Raman spectroscopy of biologically important molecules
Kuižová, Alžbeta ; Kočišová, Eva (advisor) ; Holoubek, Aleš (referee)
Drop coating deposition Raman (DCDR) spectroscopy is a special method of Raman spectroscopy, which is based on the evaporation of solvent from a drop of solution or suspension on a hydrophobic surface. This typically leads to the formation of ring-shaped drying pattern, often called as "coffee ring". As a result a preconcentration of a material and higher intensity of Raman signal in comparison with Raman scattering from solution is obtained. In this work several hydrophobic surfaces with different roughness and hydrophobicity were compared: a smooth substrate with polytetrafluorethylen (pPTFE) coating and nanorough substrates where surface hydrophobicity was formed by deposited cupper or argent nanoparticles with different concentration. It was shown that for DPPC liposome suspension stronger preconcentration is obtained by means of a nanorough substrate. When different nanorough substrate compared, no better improvement was acquired. As for the drying of drops at different temperatures (from 15řC to 60řC) deposited on the smooth pPTFE substrate and the substrate with argent nanoparticles, it was observed that Raman spectra did not reveal any spectral changes corresponding to phase transition of lipid. In case of drying at temperatures higher than a temperature of the phase transition, non-homogeneities...
Comparison of sensitivity of drop coating deposition Raman spectroscopy and surface enhanced Raman spectroscopy for study of biologically important molecules
Sayedová, Shirin ; Kočišová, Eva (advisor) ; Hofbauerová, Kateřina (referee)
The main objective of this work was to compare the sensitivity of two Raman spectroscopy methods, namely the method of drop coating deposition Raman spectroscopy and surface-enhanced Raman spectroscopy for selected biologically significant molecules: dipicolinic acid, acetylsalicylic acid, methylene blue and riboflavin. For the DCDR experiments three hydrophobic surfaces were used: commercial substrate Tienta, polished CaF2 substrateand surface with copper nanoparticles with a gradient of hydrophobicity. Two commercial surfaces were used for the SERS method. Both techniques are suitable for sample measurement at low concentrations and with small initial volumes of solutions. The DCDR method, in contrast to the SERS method, allowed to work with higher excitation radiation power. The SERS technique was markedly more sensitive for a selection of suitable SERS active surface. The spectra obtained by the SERS method were influenced by the way of adsorption of the molecules to the surface. By studying the surface with a gradient of hydrophobicity, we have revealed an effect on the shape of dried drops. The dependence on Raman intensity was not found in the case of methylene blue. For both methods we determined the limit concentrations of solutions of measured molecules that can be detected. We have shown that the...
Polyphosphates in microalgae: monitoring of their accumulation and intracellular localization by means of Raman microscopy
Suja, Matyáš ; Mojzeš, Peter (advisor) ; Kočišová, Eva (referee)
Phosphorus is widely used in agriculture, where it promotes the growth of crops and increases the profitability of soil. Together with a growing world population, there is a dramatic increase in consumption of this important element. However, the global phosphate deposits are finite and are expected to be depleted in the next few decades. It is therefore important to find an effective way of recycling, which could be represented by single-celled microscopic algae. Microscopic algae are able to accumulate large quantities of phosphorus from the surrounding environment and to store this phosphorus, among others, in the form of polyphosphates. Polyphosphates are high-energetic biomolecules which are contained in the cells of plant as well as animal kingdom. They play a key role in a vast number of vital processes. Raman microscopy can be applied to study metabolism and distribution of biomolecules at a cellular level without the need of a special preparation of the specimen before the measurement. The subject of this bachelor thesis consists of development of methodologies that are needed for studying the accumulation and intracellular localization of polyphosphates in microalgae by means of Raman microscopy.
Interakce liposomů s porfyriny studována pomocí Ramanovy spektroskopie kapkově nanášených povlaků
Vaculčiaková, Lenka ; Kočišová, Eva (advisor) ; Holoubek, Aleš (referee)
Water-soluble cationic porphyrins have been studied in relation to antisense therapy and they have been successfully used to enhance the delivery of oligonu- cleotides to cells. The main focus of this study was to characterize the mech- anism of interaction of liposomes as model membranes, and porphyrins. We applied the drop coating deposition Raman spectroscopy (DCDR) to study com- plexes of liposomes and porphyrins. DCDR allowed us to measure complexes of low concentration as it uses the 'coffee ring' effect to concentrate the sample at the edge of a drop. We studied four different complexes combined of lipids: 1, 2−dipalmitoyl−sn−glycero−3−phosphocholine, 1, 2−dioleoyl−sn−glycero− 3 − phospho − (1 − rac − glycerol) and metalloporphyrins: copper 5, 10, 15, 20 − tetrakis(1 − methyl − 4 − pyridyl)porphyrin, copper 5, 10, 15, 20 − tetrakis(4 − sulfonatophenyl)porphyrin. We have found that the way these two components interact strongly depends on a specific lipid and porphyrin used. We observed partial incorporation of porphyrins into the liposome bilayer, their localisation to the surface of the liposome or the change of the conformation and ordering of lipid molecules. Moreover, we have found that the distribution of porphyrins in the dried drop is randomly non-homogenous. 61
Factors underlying parental decisions about childood vaccination
Kočišová, Eva ; Podaná, Zuzana (advisor) ; Hamplová, Dana (referee)
The presented thesis deals with the issue of mothers' decision-making in relation to their child's vaccination against pneumococcal infections. An on-line survey of mothers was conducted (n = 180) in order to obtain data for the theoretical model based on the theory of planned behavior (TPB). A hierarchical logistic regression was then performed in order to analyze the model with the intention to vaccinate as the dependent variable. The results of the regression analyses were supplemented by results of correlation analyses and non-parametric tests. The theory proved itself as a strong predictive instrument and the results suggest that the attitude is the main predictor of the decision in this non-representative sample of mothers. The subjective norm, as the second construct of the TPB, contributes only in certain case and the perceived behavioral control was not found influential at all. The perception of thread of contraindications of the vaccine proves also influential next to the attitude. The beliefs that mothers hold about the vaccine were analyzed according to mothers intentions to vaccinate (n = 70) or not to (n = 110). These results support the idea that mothers, especially those who do not want to vaccinate their children against pneumococcal infections, decide particularly according to...
Drop coating deposition Raman spectroscopy of liposomes with different compositions
Antalík, Andrej ; Kočišová, Eva (advisor) ; Holoubek, Aleš (referee)
Method of drop-coating deposition Raman spectroscopy is a special tech- nique that employs deposition of a small droplet of the sample on a hydro- phobic surface with subsequent solvent removal by evaporation. As a result the concentrated material forms a ring at the edge of the droplet. This techni- que has proven to be efficient for liposome studies at low concentrations. We focused on a study of spectral changes and ring formation in phosphatidylcho- line liposomes due to increasing amount of cholesterol. Higher concentration of cholesterol didn't cause significant changes in membrane structure, such as phase transition, however the ring wasn't formed. Second part of this bache- lor thesis concerns with the search for some alternative surface to previously used SpectRIM TM DCDR plates made by Tienta Sciences, Inc. which are no longer available. The polished calcium fluoride glass (CaF2) seems to be the most suitable for the further use from all tested surfaces. Raman signal at the other surfaces was either weak or spectral bands that don't belong to lipid were observed.
Spectroscopic study of interaction of antimicrobial peptides with model membranes
Tesař, Adam ; Kopecký, Vladimír (advisor) ; Kočišová, Eva (referee)
Antimicrobial peptides (AMP) have a great potential in medicine and pharmacy. Mechanism of their impact is an interaction with a cell membrane leading to the penetration of the membrane. The way of disruption of the cell membrane is not completely understand, therefore we focused on the interaction of AMP HAL-1, isolated from the venom of the bee Halictus sexctinctus, with a model membrane of 100 nm liposomes consisting of phosphatidylcholin and phosphatidylglycerol. Circular dichroism and infrared spectroscopy (FTIR) proved the change of the secondary structure from the random coil of free HAL-1 to -helix in an interaction with the membrane. The next step was preparation of the lipid bilayer on the surface of ATR prism, which will enable usage of the polarized FTIR spectroscopy to study the interaction of AMP with model membranes in future. Therefore, the ATR-FTIR spectroscopy and factor analyses were applied to study dynamics of drying of the liposomes and their subsequent hydration also with an addition of HAL-1. We focused on the stabilization of the system. Hydratation of the lipid bilayer by 2 µl sample showed stability for minutes, nevertheless after dilution the stabilization decay in minutes. The protective influence of the peptide on the lipid bilayer and slowing down of the drying out of the...
Improved determination of DNA duplex stability by using UV spectroscopy
Víšová, Ivana ; Štěpánek, Josef (advisor) ; Kočišová, Eva (referee)
This work deals with determination of thermodynamic parameters concerning the temperature induced decomposition of DNA duplexes. Precise temperature dependences of solution UV absorption spectra have been measured for several concentrations. Proposals and tests of various data analysis procedures, with aim to find out optimal way how to determine the thermodynamic potentials changes, represent the core of the work. It has been demonstrated that the combination of a factor analysis and a fit of thermodynamic equations to temperature dependences of obtained coefficient values, enables these parameters to be obtained from a measurement performed for only one concentration and with better precision than by using the so far recommended method based on a melting temperature determination for several concentrations.
Study of liposomes by using of drop coating deposition Raman spectroscopy
Vodáková, Adéla ; Kočišová, Eva (advisor) ; Bednárová, Lucie (referee)
in english: Goal of the Bachelor Thesis was an optimization of liposome membrane preparation with different composition for the drop coating deposition Raman (DCDR) method, measuring of the DCDR spectra from dried droplets and their interpretation. The DCDR method lies in deposition of small volume of suspension (~μl) on special surface and measuring of Raman spectra from the ring formed at the edge of the dried droplet. The main advantage of used method is the possibility of measuring spectra from the sample with low concentration. Our results show that the DCDR method is very useful in studies of biological membranes with different composition. Two synthetic lipids and one natural extract were chosen for making a comparison. We have found out that spectra obtained from the ring of dried droplet are not different from the spectra measured in the suspension. The important characteristic of spectra is that dried droplet keeps the same lipid phase as in suspension. Spectral mapping proved good reproducibility of the signal inside the ring.

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