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New technique on a chip for rapid detection of biological materials
Pejović Simeunović, Jelena ; Foret,, František (referee) ; Táborský,, Petr (referee) ; Hubálek, Jaromír (advisor)
Tato práce navrhuje techniku separace a detekce na čipu pro kvantové tečky (QD, „quantum dots“) konjugované s různými proteiny, za účelem sledování vlivu vazebného činidla na potlačení intenzity uorescence QD způsobené konjugací s proteinem a za účelem provedení multianalytické imunoanalýzy k identifikaci malých množství daného proteinu. Za optimálních podmínek byly biokonjugované QD úspěšně odděleny od těch nezkonjugovaných během 10 minut. Částice a cílové roztoky byly smíchány a detekce na čipu byla provedena za pomoci zařízení vyvinutého v naší laboratoři. Byl použit pouze jeden zdroj excitačního světla v kombinaci s několika filtry pro různé emisní vlnové délky. Fluorescence emitovaná dvěma typy konjugovaných QD mohla být poté zaznamenána současně, protože QD emitovaly světlo na různých vlnových délkách, ačkoliv byly excitovány při stejné vlnové délce. Smícháním dvou typů QD biokonjugovaných se dvěma druhy proteinů a protilátek jsme dokázali detekovat imunokomplexní píky s různými plochami. Plocha pod píkem závisela na koncentraci QD a antigenů, na postupu reakcí protilátka–antigen a ukázalo se, že je lineárně korelována s koncentrací antigenu. Ukázali jsme, že kapilární elektroforéza QD na čipu může být použita jako citlivá technika pro detekci biologických molekul. Hlavními výhodami této metody jsou jednoduchost, malé požadavky na objem vzorku i činidla a také vysoká účinnost separace.
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Energetic interactions between electon-donors and acceptors for photovoltaic solar cells
Hrabal, Michal ; Heinrichová, Patricie (referee) ; Vala, Martin (advisor)
The aim of this bachelor thesis is to study a charge transfer between materials that could be used for development of new organic solar cells. The charge transfer is studied by a quenching of fluorescence. The thesis is divided into theoretical and experimental part. The basic knowledge needed for correct interpretation of measured data is summarized in the first part. Special attention is paid to the photoinduced electron transfer. Then, the processes of conversion of solar energy into electric energy and properties of potential materials are also discussed. Architecture of organic solar cells is mentioned in the end of the work. The practical part contains the study of quenching of fluorescence by fullerene derivatives and compares the efficiency of quenching to standard materials.
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Novel diketopyrrolopyrroles for organic photovoltaics
Hrabal, Michal ; Zmeškal, Oldřich (referee) ; Vala, Martin (advisor)
The aim of this diploma thesis is to conduct optical and photovoltaic characterization of derivatives of diketopyrrolopyrrole (DPP) as materials suitable for fabrication of bulk heterojunction organic solar cells. The charge transfer from donor material (DPP) to acceptor material (PCBM) is studied by a quenching of fluorescence. The photovoltaic response is studied by current – voltage characteristic which can tell us crucial parameters such as shor circuit current density Jsc, open circuit voltage Voc, fill factor FF and power conversion efficiency PCE. Optical characterization was carried out for symmetrical DPP derivatives (U69 and U97) which both contained diphenylaminstilbene moiety and differed in N-alkyl group. On the other hand photovoltaic characterization was conducted for analogous but asymmetrical materials (U70 and U99). Material U29 was characterized as well but its properties proved to be very poor. Both these characterizations tell us that materials with shorter solubilization groups (U69 and U99) are more suitable candidates. Achieved PCE for U70 was 0,74 % and for U99 up to 1,39 %. From these values one can say that small molecule organic materials can be used for fabrication of solar cells.
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Fluorescence quenching in colloid research
Srholcová, Barbora ; Ing. Michal Zavadil, Ph.D (referee) ; Pekař, Miloslav (advisor)
Allready known theoretical observations about utilization of the emission quenching of fluorescence probes in the study of colloids were summarized by finding in the literature search and on the internet, especially the determination of the probe´s location, the aggregation numer and finally the effective viscosity. In the experimental part was studied quenching of the pyrene in the medium of the anionogenic and non-ionic surfactants. As a quenchers were used iodobenzene, tetracyanoethylene and cetylpyridiniumchloride. Selected experiments helped by finding out the aggregation number of the micelle.
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Effect of chemical modification of humic acids on their interactions with organic ions
Fryšová, Eva ; Weidlich, Tomáš (referee) ; Sedláček, Petr (advisor)
This master thesis deals with the interaction of humic acids with organic ions and effect of chemical modification of humic acids on this interaction. Rhodamine 6G was used as a model organic ion. The interaction were studied by fluorescence quenching, dialysis in diffusion cells and differential UV-VIS spectroscopy. Results showed that the bond between the reactants was not primarily dependent on carboxylic functional groups of humic acids. Fluorescence experiments indicated static quenching mechanism and differential UV-VIS spectroscopy demonstrated the existence of - interactions.
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Energy transfer and hydrophobic domains in colloidal systems
Kučerová, Petra ; Čeppan, Michal (referee) ; Pekař, Miloslav (advisor)
In this thesis resonance energy transfer between perylene and fluorescein in tetradecyltrimethylammonium bromide (TTAB) solution was studied. The influence of addition of native or modified sodium hyaluronate on resonance energy transfer was also investigated. The addition of native sodium hyaluronate supports energy transfer at lower fluorescein concentrations and the addition of modified sodium hyaluronate influences the maximal value of energy transfer effectivity. Strong influence on the critical micelle concentration (CMC) values with the addition of sodium hyaluronate during CMC of TTAB determination was investigated. The data indicates not only micelles formation, but also formation of aggregates of sodium hyaluronate with TTAB. Aggregation numbers of TTAB with addition of native and modified sodium hyaluronate by the quenching of pyrene by cetylpyridinium chloride (CPC) was investigated. The addition of sodium hyaluronate into the solution of TTAB changes the average mean aggregation number. Solute exchange between micelles of TTAB and the influence of addition of modified sodium hyaluronate on this exchange was also investigated. No solute exchange between micelles in TTAB and in TTAB with added modified sodium hyaluronate was discovered during this experiment.
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Fluorescence quenching in study of aggregation behavior of colloids
Srholcová, Barbora ; Hrdina,, Radim (referee) ; Pekař, Miloslav (advisor)
This work focuses on examination of hyaluronan-sulfactant aggregates in term of determination of aggregate number. The value of critical micellar concentration (CMC) cetyltrimethylammonium bromide (CTAB) in three different solvents (water, phosphate buffer and physiological solution). Next the effect of the native hyaluronan supplement on the value of CMC was examined. It wasfound out that the solvent has the biggest effect on the value of CMC whilst the hyaluronan supplement affects CMC only a little. The aggregate number (Nagg) CTAB and the effect of the native hyaluronan supplement were determined out by means of fluorescence quenching. Pyrene was used as a fluorescence probe. Iodine and cetylpyridinium chloride (CPC) were used as quenchers. Sulfactant was dissolved in three different solvents (water, phosphate buffer and physiological solution). Not only the hyaluronan supplement but also the used solvent has the strong effect on the value of the aggregate number. When using 10mM CTAB dissolved in physiological solution the value of Nagg was 119 ± 4 while the value was half in buffer. Then we found out that in most cases the hyaluronan supplement reduces the value of the aggregate number.
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Counterion condensation on a polyelectrolyte: A fluorescence quenching study
Riedlová, Kamila ; Štěpánek, Miroslav (advisor) ; Humpolíčková, Jana (referee)
In this thesis, we studied the counterion condensation on the polyelectrolyte chain by means of the fluorescence quenching technique, using poly(methacrylic acid) (PMAA) labelled by the naphthyl group either at the end or in the middle of the chain and cesium ions as counterions which act as the fluorescence quencher. Both polymer samples were characterized by dynamic light scattering. The interaction of Cs+ ions with the polyelectrolyte was studied in solvents differing in the dielectric permittivity, using mixtures of water with 1,4-dioxane. The results confirm that fluorescence quenching is enhanced by the counterion condensation and that this process is more pronounced in the case of the naphthyl moiety localized in the middle of the PMAA chain.
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New technique on a chip for rapid detection of biological materials
Pejović Simeunović, Jelena ; Foret,, František (referee) ; Táborský,, Petr (referee) ; Hubálek, Jaromír (advisor)
Tato práce navrhuje techniku separace a detekce na čipu pro kvantové tečky (QD, „quantum dots“) konjugované s různými proteiny, za účelem sledování vlivu vazebného činidla na potlačení intenzity uorescence QD způsobené konjugací s proteinem a za účelem provedení multianalytické imunoanalýzy k identifikaci malých množství daného proteinu. Za optimálních podmínek byly biokonjugované QD úspěšně odděleny od těch nezkonjugovaných během 10 minut. Částice a cílové roztoky byly smíchány a detekce na čipu byla provedena za pomoci zařízení vyvinutého v naší laboratoři. Byl použit pouze jeden zdroj excitačního světla v kombinaci s několika filtry pro různé emisní vlnové délky. Fluorescence emitovaná dvěma typy konjugovaných QD mohla být poté zaznamenána současně, protože QD emitovaly světlo na různých vlnových délkách, ačkoliv byly excitovány při stejné vlnové délce. Smícháním dvou typů QD biokonjugovaných se dvěma druhy proteinů a protilátek jsme dokázali detekovat imunokomplexní píky s různými plochami. Plocha pod píkem závisela na koncentraci QD a antigenů, na postupu reakcí protilátka–antigen a ukázalo se, že je lineárně korelována s koncentrací antigenu. Ukázali jsme, že kapilární elektroforéza QD na čipu může být použita jako citlivá technika pro detekci biologických molekul. Hlavními výhodami této metody jsou jednoduchost, malé požadavky na objem vzorku i činidla a také vysoká účinnost separace.
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Counterion condensation on a polyelectrolyte: A fluorescence quenching study
Riedlová, Kamila ; Štěpánek, Miroslav (advisor) ; Humpolíčková, Jana (referee)
In this thesis, we studied the counterion condensation on the polyelectrolyte chain by means of the fluorescence quenching technique, using poly(methacrylic acid) (PMAA) labelled by the naphthyl group either at the end or in the middle of the chain and cesium ions as counterions which act as the fluorescence quencher. Both polymer samples were characterized by dynamic light scattering. The interaction of Cs+ ions with the polyelectrolyte was studied in solvents differing in the dielectric permittivity, using mixtures of water with 1,4-dioxane. The results confirm that fluorescence quenching is enhanced by the counterion condensation and that this process is more pronounced in the case of the naphthyl moiety localized in the middle of the PMAA chain.
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