Made available in DSpace on 2014-10-09T12:24:13Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:12Z (GMT). No. of bitstreams: 1 01038.pdf: 2373326 bytes, checksum: 6700d091a3c179334b03259e2a632223 (MD5) / Dissertacao (Mestrado) / IEA/D / Escola Politecnica, Universidade de Sao Paulo - POLI/USP

Orientadores: Jorge Humberto Nicola, Ester Maria Danielli Nicola / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-13T06:03:03Z (GMT). No. of bitstreams: 1 Hernandez_JoaoWagnerRodrigues_D.pdf: 4481265 bytes, checksum: 5351d4ae13e0c0baa8fd480610047a9b (MD5) Previous issue date: 2009 / Resumo: A pesquisa de fluorescência nativa em tecidos biológicos tem despertado grande interesse na Biologia e Medicina. A fluorescência óptica tornou-se instrumento indispensável aos diagnósticos, sendo um método eficiente e não invasivo. Neste trabalho investigamos a presença de fluorescência nativa em áreas corpóreas de ratos Wistar, subdivididos em dois grupos: um com alimentação normal e outro com dieta de glicose 5%. Em áreas internas (experimento 1), não ficou evidenciada a fluorescência nativa em animais com alimentação normal de água e ração. Nos animais submetidos à dieta de glicose, observamos a presença de fluorescência nativa vermelha, captada por espectroscopia, alcançando um pico máximo de emissão luminosa em 120 horas de dieta e retomando valores iniciais, quando sua dieta voltou ao normal. O conteúdo do lúmen intestinal foi analisado espectroscopicamente e por prova bioquímica. O gráfico obtido foi semelhante ao da PpIX e o teste bioquímico (Eales modificado ) resultou positivo à presença de substância porfirínica. A fluorescência em áreas externas, bolsa escrotal, focinho, pata e cauda, também foi pesquisada nas mesmas condições de dieta (normal e glicosada), evidenciando que animais com dieta normal, não apresentaram fluorescência e nos de dieta de glicose, deparamos com pico máximo de fluorescência em 120 horas de dieta e retomando valores iniciais, quando sua dieta voltou ao normal. A fluorescência nativa encontrada nos animais submetidos à dieta glicosada, evidencia uma nova condição fisiopatológica e que se assemelha a um quadro de porfiria reversível, bem identificada e documentada pelo experimento 2. Os resultados mostram a importância da espectroscopia óptica como um método de diagnóstico precoce, simples e confiável, para uso em diversos tipos de doenças ou disfunções com acúmulo de pigmentos fotossensíveis. Chama, ainda, a atenção para situações em que fluorescências nativas possam ser tomadas como diagnóstico falso-positivo de alterações patológicas ou não. / Abstract: The research of native fluorescence in biological tissues has aroused great interest in Biology and Medicine. The optic fluorescence became an important instrument for the diagnosis, being an efficient and non-invasive method. In this work we investigated the presence of native fluorescence in corporal areas of Wistar rats, subdivided in two groups: one with normal feeding and another one with glucose diet 5%. In the intestinal tract (Experiment 1), there was no evidence of fluorescence in animals with normal feeding of water and ration. In the animals submitted to the glucose diet, we observed the presence of red native fluorescence, caught by spectroscopy, reaching a maximum peak of luminous emission in 120 hours of diet with the return to normal values after the re-introduction of normal diet. The content of the intestinal lumen was analyzed spectroscopically and by biochemical test. The obtained graph was similar to the one of the PpIX and the test modified by Eales resulted positive to the presence of porfirinic substance. For Experiment 2, a group of 30 animals were kept at the same diet conditions (normal and glucose 5%) up to 120 hours. Four external areas were selected for the study (paw, tail, nose and scrotum). The group os animals under glucose diet presented a marked fluorescence on the selected areas with a maximum pick at 120hours. After 24 and 48 hours of reestablishment of the regular solid diet the fluorescence decreased disappearing totally at 48 hour. The native fluorescence found in the animals submitted to the glucose diet, evidences a physiopathological condition and it is similar to a condition of reversible porfiria, well identified and registered by Experiment 2. The results show the importance of the optic spectroscopy as a method of precocious, simple and trustworthy diagnosis, for use in diverse types of illnesses or dysfunctions with accumulation of photosensitive pigments. It also calls attention, for situations where native fluorescence can be taken as false-positive diagnosis of malignant alterations. / Doutorado / Ciencias Biomedicas / Doutor em Ciências Médicas

Orientador: Teresa D. Z. Atvars / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-04T07:47:01Z (GMT). No. of bitstreams: 1 Baldi_LeonardoDelaColeta_M.pdf: 4843408 bytes, checksum: 8a861f165970d1fd6ff07a8b5889c676 (MD5) Previous issue date: 2004 / Mestrado / Físico-Química / Mestre em Química

The development of facile and reliable methods to image and detect important biomolecules has drawn considerable attention owing to their potential applications in clinical, bioanalytical and forensic analysis. One-photon microscopy (OPM) has traditionally been used in cell biology research. However, probes based on OPM are associated with shortcomings including photobleaching, cell damage, and intracellular autofluorescence interference. Many researchers are seeking better tools to overcome these obstacles. Two-photon microscopy (TPM) is a convenient and powerful tool to explore the intracellular environment and provides the opportunity to overcome the abovementioned obstacles. Probes based on TPM have become important for bioimaging and sensing because of their low photodamage, reduced fluorescence interference, and better tissue penetration depth. With the development of fluorescence molecules in recent decades, a wide range of organic fluorescence probes based on TPM has been rapidly developed and used in biomedicine and bioimaging. Cyanine dye, one of the classic synthetic dyes, continues to be used in many fields, especially in bio-related applications, owing to its ability to interact with biomolecules through non-covalent and electrostatic bonds. Based on cyanine models, we designed a series of structural modifications of cyanine fluorophores used as two-photon (TP) probes to detect and image the intracellular environment in which new cyanine compounds, namely SLSO3, SLCOOH-Pr, F-SLOH, SLOH, Me-SLM, SLE, SAM, SAOH, SLG, F-SPG, SLOH-Pr, SLAD, F-SLAD, Me-SLG, SLNA, SLAD-Pr, SLCOOH, SLAce, SLM, SPC, SIOH, PSIOH, DMA-SLOH, DBA-SLOH, DPA-SLM, GBPM, HBBM, HBLM, SBM, SIBM, SIM, PLOH, and PTM, was successfully synthesized. All of these newly designed compounds were characterized with 1H NMR, 13C NMR, and HRMS and found to show good agreement with the desired structures. To our surprise, some of the novel cyanine molecules were also able to detect and image amyloid-β (Aβ) peptide species and showed excellent biological properties including neuroprotective effects against the cytotoxicity induced by different forms of Aβ species, blood-brain barrier permeability, and high in vivo stability. The photophysical and biological properties of these newly synthesized compounds included optical properties such as UV-vis absorption, emission, fluorescence quantum yield in different solvents, dissociation constant determined by fluorescence titration, and circular dichroism spectroscopy, cytotoxicity assay, neuroprotection, and inhibition of Aβ aggregation were investigated.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第15390号 / 工博第3269号 / 新制||工||1492(附属図書館) / 27868 / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 大江 浩一, 教授 辻 康之, 教授 村田 靖次郎 / 学位規則第4条第1項該当

Doctor of Philosophy / Department of Chemistry / Daniel A. Higgins / This dissertation describes the application of fluorescence microscopy techniques to investigations of mass transport phenomena in self-assembled nanomaterials. The microscopic morphologies of the materials and the mass-transport dynamics of probe molecules dispersed within them were assessed with high temporal and spatial resolution by single molecule imaging and spectroscopic methods. Three distinct sets of experiments were performed in completing the work for this dissertation. In the first study, single molecule imaging was employed to explore the interactions and field-induced migration of double-stranded DNA (ds-DNA) molecules with nanostructured Pluronic F127 gels. While DNA interactions with nanostructured gels have been explored in the past, none had apparently looked at these interactions in gels comprising hexagonally ordered arrays of cylindrical micelles. Therefore, these studies focused on materials DNA dispersed in flow aligned hexagonal F127. DNA molecules were found to be strongly confined in the hexagonal mesophase structures from their elongation, alignment, and exclusively occurred electrophoretic migration in the direction parallel to the cylinder long axis. These observations will lead to a better understanding of macromolecular interactions with nanostructured gels like those now being investigated for use in drug delivery and chemical separations. In the second study, imaging-fluorescence correlation spectroscopy (imaging-FCS) was used to study the rate and mechanism of sulforhodamine B (SRB) dye within novel bolaamphiphile-based self-assembled nanotubes. These nanotubes were only recently developed and their mass transport properties remain largely unexplored. The nanotubes employed here are unique because they incorporate amine groups and glucose groups on their inner and outer surfaces, respectively. Wide-field fluorescence video microscopy was first applied to locate and image dye-doped nanotubes dispersed on a glass surface. Imaging-FCS was employed as it allows for the dynamics to be recorded simultaneously from a large sample region, thus the SRB mass transport within nanotubes can be spatially resolved. The coulombic interactions between cationic ammonium ions on the inner nanotube surface and the anionic SRB molecules was shown to play a critical role in governing dye dynamics under varied pH and ionic strength conditions. Mass transport of SRB within the nanotubes is concluded to occur by a desorption-mediated Fickian diffusion mechanism. In the third set of experiments, solvatochromic dye molecules were employed in novel imaging-FCS studies of the role played by partitioning in governing mass transport phenomena within the same organic nanotubes used above. Two forms of the solvatochromic dye Nile Red (NR) were employed: the commercial hydrophobic form of NR, and a more polar derivative 2-hydroxybenzophenoxazinone (named NR-OH). The partitioning of dye molecules within the nanotubes was investigated assessing the diffusion rate for each dye. The preliminary results suggested NR and NR-OH preferentially partitioned into the tube walls and the ethanol phase filling the tubes, respectively. The diffusion coefficient data indicated NR-OH diffused faster than NR, consistent with the presence of NR-OH in a relatively less viscous environment (e.g., the ethanol phase filling the tubes). The results of these studies afford information essential to the use of organic nanotubes in controlled drug release and possibly in catalysis applications.

No description available.

In this thesis I have given an account of the experimental work carried out by me at Rhodes University from the beginning of 1954 to the end of 1955, and the analysis of the results which was completed during the following two years, 1956 and 1957. The dissertation is divided into two sections; Part I deals with the photo fluorescence spectra of a large group of organic compounds, and Part 2 describes an investigation of the photo-fluorescence properties of and energy transfer in liquid organic solutions.

From introduction: The Fluorescence Excitation Spectrum or anthracene is known to vary considerably with the age and condition or the crystal. This thesis represents an attempt to improve the understanding of these variations. To put the problem on a quantitative basis it was found necessary to know both the ultraviolet reflection and absorption spectra. Reports of the reflection spectrum appear to have been confined to the case of polarised incident light. In addition the reflectivity measurements are always reported for a freshly cleaved surface. For these reasons the reflectivity of anthracene for various conditions of the reflecting surface was measured with unpolarised light. These varying reflectivities were used to further knowledge of the chemical processes at the crystal surface, as well as being used directly in the calculation of fluorescence excitation spectra. Reflection spectra with a- and b- crystallographic axis polarisations were also obtained. Since such spectra are reported in the literature it was possible, by comparison, to conclude that the experimental methods used in this thesis yielded valid results. The polarised measurements were used to obtain optical constants for the crystal. In the interests of readability most of the complicated process of converting the reflectivities to optical constants is dealt with in three appendices to the thesis.

The interaction of different formulations of the antifungal drug amphotericin B (AmB) with model cell membranes was studied and new techniques of measuring this interaction using electrochemical and/or spectroscopic methods were developed. Two model cell membrane systems were used: sterol-free lipid monolayers adsorbed to a Hg electrode and sterol-free or sterol-containing floating lipid monolayers on a Langmuir trough. Electrochemical control over the adsorbed monolayer allowed the defectiveness of the layer to be varied and the interaction of AmB with both well-ordered and defective monolayers characterized. Measurements of monolayer capacitance and permeability were used to indicate the nature of the interaction. Capacitance provides a measure of the lipid organization, while permeability was measured via electro reduction of thallium (I)cation. The three AmB formulations and two control samples were examined and showed different interaction behaviour. The disruption of lipid order and permeabilization induced by the two commercial formulations correlated generally with in vivo studies of their toxicity. An experimental and possibly less toxic AmB formulation made monolayer significantly more permeable. In situ fluorescence microscopy of the monolayer on Hg was carried out after introducing a low concentration of fluorophore into the layer. Fluorescence intensity as a function of electrode potential was measured and was used to characterize the lipid on Hg model membrane system before we attempted to measure AmB's influence on the fluorescence. The fluorescence excitation and emission spectra of AmB itself were measured ex situ for two of the formulations. Using added surfactant to control AmB aggregation state, the relationship between AmB aggregation and its fluorescence properties was examined. We discovered AmB to have unusual dual fluorescence properties, the extent of which differed between formulations. We measured AmB's fluorescence in situ as the drug interacted with floating lipid monolayers on the Langmuir trough. Both the variation in fluorescence during compression of a mixed AmB/lipid monolayer and penetration of AmB into a phospholipid monolayer were measured. This experimental setup was configured to collect fluorescence only from AmB at the monolayer, and not from AmB in bulk solution. Fluorescence excitation was made using a laser diode extracted from a consumer electronics device. / Science, Faculty of / Chemistry, Department of / Graduate