Zugl.: Kaiserslautern, Techn. Univ., Diss., 2009

University, Diss., 2002--Regensburg.

Universiẗat, Diss., 2004--Münster (Westfalen).

This thesis begins with a brief review about the role and importance of the small molecules containing fluorine atoms in medicine and imaging. Then, the first part of the thesis will discuss the synthesis, purification and characterization of pentamethine cyanine dyes. The structure identification of the final dyes is done by using 1H NMR, 13C NMR, 19F NMR, and mass spectrometry. The studies performed after full characterization were the determination of optical and physicochemical properties. After these properties were performed, the fluorophores were evaluated to be good candidates for in vivo testing.

For determination of structures and structural dynamics of proteins organic fluorophores are a standard instrument. Intra- and intermolecular contact of biomolecular structures are determined in time-resolved and stationary fluorescence microscopy experiments by quenching of organic fluorophores due to Photoinduced Electron Transfer (PET) and dimerization interactions. Using PET we show in this work that end-to-end contact dynamics of serine-glycine peptides are slowed down by glycosylation. This slow down is due to a change in reaction enthalpy for end-to-end contact and is partly compensated by entropic effects. In a second step we test how dimerization of MR121 fluorophore pairs reports on end-to-end contact dynamics. We show that in aqueous solutions containing strong denaturants MR121 dimerization reports advantageously on contact dynamics for glycine-serine oligopeptides compared to the previously used MR121/tryptophane PET reporters. Then we analyze dimer interactions and quenching properties of different commercially available fluorophores being standards in Förster Resonance Energy Transfer (FRET) measurements. Distances in biomolecules are determinable using FRET, but for very flexible biomolecules the analysis of masurement data can be distorted if contact of the two FRET fluorophores is likely. We quantify how strong the quenching of fluorophore pairs with two different or two identical fluorophores is. Dimer spectra and association constants are quantified to estimate if fluophores are applicable in various applications, e.g. in FRET measurements with unstructured peptides and proteins. / Zur Charakterisierung von Proteinen werden in der fluoreszenzbasierten Mikroskopie organische Farbstoffe benutzt, um strukturelle Informationen bzw. Informationen über dynamische Prozesse zu gewinnen. In der zeitaufgelösten und stationären Fluoreszenzmikroskopie können hiermit Kontaktprozesse durch photoinduzierten Elektronentransfer und auch Dimerisierung der Fluorophore analysiert werden. In dieser Arbeit wird mittels photoinduziertem Elektronentransfer PET gezeigt, dass Glykosylierung End-zu-End Kontaktkinetiken verändert. Sehr flexible Serin-Glycin Peptide zeigen glykosyliert langsamere Kinetiken durch Veränderung der Reaktionsenthalpie der Kontaktreaktion beider Peptidenden verglichen zu unglykosylierten. Diese enthalpischen Beiträge werden zum Teil von entropischen Beiträgen kompensiert. Außerdem wird gezeigt, dass Glycin-Serin Peptiddynamiken auch mittels Farbstoffpaaren gemessen werden können, die auf Löschwechselwirkungen durch Dimerisierung beruhen. Die Stärke dieser Löschwechselwirkungen hängt vom Farbstoffpaar ab. In Lösungen mit Denaturierungsmitteln können Farbstoffpaare des Fluoreszenzfarbstoffes MR121 vorteilhaft für Messungen von Dynamiken von Glycin-Serin Peptiden genutzt werden. Die Dimerwechselwirkungen können bei sehr flexiblen Biomolekülen und möglichem Kontakt von Fluorophoren die konventionelle Analyse von Förster Resonanz Energie Transfer (FRET) Messungen erschweren. Wir untersuchen an Glycin-Serin Oligopeptiden das Dimerisierungsverhalten kommerziell erhältlicher Fluorophore, die in FRET Messungen verwendet werden. Für gleiche und verschiedene Fluorophore wird die Löschung durch Dimerwechselwirkungen quantifiziert. Dabei werden Dimerspektren und Assoziationskonstanten für Dimerisierungsreaktionen bestimmt. Letztere helfen bei der Abschätzung, ob Fluorophorpaare für verschiedene Anwendungen geeignet sind, zum Beispiel in FRET-Messungen in unstrukturierten Peptiden und Proteinen.

Regensburg, Univ., Diss., 2003. / Erscheinungsjahr an der Haupttitelstelle: 2003.

This thesis focuses on the study of the life of a fluorescent dye. It also examines changes in its emission spectrum determined with the aid of development of fluorescence intensity over the long term sensing in several kinds if of cella. The general part of the thesis with the issues of confocal microscopy, fluorescent radiation and maks. Furthermorer, an analysis of methods for measuring fluorescence lifetime is done. In the thesis there is elaborated a description of the program, whitch was designed for the analysis of the collected output of the used confocal microscope. Sebsequently, the results are evaluated.

Eight fluorescent indicators were evaluated for their ability to detect the corrosion of aluminum metal substrates. The fluorophore Rhodamine-salicylaldehyde (RSA) was selected as a candidate for further study based on its ability to bind and detect aluminum ions at low concentrations, its selectivity for aluminum ions, its long-term stability, its solubility in our solvent-based epoxy formulation, and its compatibility with our testing method. A recent publication suggested that an alternative method of fluorescence activation was possible—an acid-promoted ring opening that occurred in the absence of metal ions. To prove the capability of RSA to bind aluminum ions, thorough 1H and 27Al nuclear magnetic resonance spectroscopy, mass spectrometry, and fluorescence analysis was conducted. It was found that RSA bound aluminum ions, with a preferred binding stoichiometry of 2:1 RSA/Al. Long-term immersion and salt spray corrosion studies were conducted to investigate the ability of RSA to detect corrosion on aluminum substrates. Aluminum panels were coated with epoxy coatings that contained the fluorescent indicator. Following optimization, a linear relationship between corroded area and time of immersion/exposure to salt fog was observed.

No description available.

No description available.