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Desenvolvimento e avalia??o da atividade antitumoral de nanotubos de titanatos modificados com quercetina em c?ncer de bexigaAlban, Luisa 01 August 2018 (has links)
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Previous issue date: 2018-08-01 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The interest in nanostructures such as titanate nanotubes (TNTs) has grown notably in recent years due to their biocompatibility and economic viability, which makes them promising for application in the biomedical field. Quercetin (Qc) has been reported to have great potential as a chemopreventive agent widely used in the study of the treatment of diseases such as bladder cancer. Therefore, this work aimed to study the incorporation of quercetin in sodium TNTs (NaTNT) and zinc (ZnTNT), as well as characterize the nanostructures formed. In addition, it was intended to conduct Qc release tests and biological and antitumor activities in T24 lineage cells. The nanostructures of TNTs were synthesized and characterized by FTIR, MEVFEG, EDS, MET DRX and TGA techniques. The results showed that the nanostructures have a tubular structure and the exchange of Na+ ions by Zn2+, as well as the incorporation of quercetin in the structure do not alter this morphology. In addition, the interaction established between Zn and Qc increases the thermal stability of nanostructures. The release test showed that the maximum delivery of Qc
occurs after 24h and the presence of Zn controls the release of the flavonoid. Biological assays have shown that the NaTNTQc and ZnTNTQc nanostructures decrease the cellular viability of T24 after 48h in high concentrations. Furthermore, NaTNT, NaTNTQc and ZnTNT reduce the number of T24 lineage cells when combined with irradiation after 48h showing that the combination of nanostructures and ionizing energy is an attractive object of study in the treatment of bladder cancer. / O interesse por nanoestruturas como nanotubos de titanatos (TNTs) tem crescido notavelmente nos ?ltimos anos devido a sua biocompatibilidade e viabilidade econ?mica, o que os tornam promissores para a aplica??o na ?rea biom?dica. A quercetina (Qc) tem sido relatada como tendo grande potencial como agente
quimiopreventivo amplamente utilizada no estudo do tratamento de doen?as como c?ncer de bexiga. Neste sentido, este trabalho pretendeu estudar a incorpora??o de quercetina em TNTs de s?dio (NaTNT) e de zinco (ZnTNT), bem como, realizar a caracteriza??o das nanoestruturas formadas. Al?m disso, pretendeu-se conduzir testes de libera??o de Qc e atividades biol?gicas e antitumorais em c?lulas da linhagem T24. As nanoestruturas de TNTs foram sintetizadas e caracterizadas por t?cnicas de FTIR, MEV-FEG, EDS, MET DRX e TGA. Os resultados mostraram que as nanoestruturas apresentam estrutura tubular, e a troca de ?ons Na+ por Zn2+, bem como a incorpora??o de quercetina na estrutura n?o alteram esta morfologia. Al?m disso, a intera??o estabelecida entre o Zn e Qc aumenta a estabilidade t?rmica das nanoestruturas. O ensaio de libera??o mostrou que a entrega m?xima de Qc ocorre ap?s 24h e apresen?a de Zn controla a libera??o do flavonoide para o meio. Os ensaios biol?gicos mostraram que as nanoestruturas NaTNTQc e ZnTNTQc
diminuem a viabilidade celular de T24 ap?s 48h em altas concentra??es. Ainda, NaTNT, NaTNTQc e ZnTNT reduzem o n?mero de c?lulas da linhagem T24 quando combinadas com irradia??o ap?s 48h mostrando que a combina??o entre as nanoestruturas e energia ionizante se apresenta como um objeto de estudo atrativo no tratamento de c?ncer de bexiga.
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Catalytic properties of titanate nanotubes applied to dry reforming of methane / Propriedades catalÃticas de nanotubos de titanatos aplicados na reforma seca do metanoDavi Coelho de Carvalho 02 March 2016 (has links)
CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / Dry reforming of methane reaction was conducted in the presence of titanate nanotubes (TNTs) modified with Co, Ni and Pt. TNTs were synthesized by hydrothermal treatment and than these solids were either submitted to ion exchange for Ni and Co using hexahydrate nitrate solutions, or they were submitted to wet impregnation with H2Ptl6.6H2O (1% w/w of Pt) solution. The solids were characterized before and after the dry reforming of methane by elemental chemical analysis (CHN), X-ray diffraction (XRD), Raman spectroscopy, nitrogen adsorption-desorption isotherms, thermoprogrammed reduction (TPR), CO2 thermoprogrammed desorption (CO2-TPD), transmission electronic microscopy (TEM), scanning electronic microscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). Raman and XRD results showed the presence of Na2Ti3O7 phase to all sodic nanotubes, while that the nanotubes modified displayed peaks and vibrational modes relative to CoTi3O7, NiTi3O7 and PtOx/Na2Ti3O7 phases. TEM images exhibited tubular morphology composed by multi-walls, as observed by XRD and Raman. SEM-EDS results showed the nanotubes composition with M/Ti ratio lower than the theoretical (value of 0,33), due to the presence of structural water. The XPS results confirmed the presence of M(OH)2 phase (M=Co, Ni or Pt) present on nanotubes surface. TPR patterns suggested the formation of M0/MTiO3 (M = Co, Ni and Pt) after the reduction of the nanotubes at 650 ÂC. The nitrogen adsorption-desorption isotherms of sodic and modified TNTs showed isotherms type IV with an essentially mesoporous structure. CO2-TPD patterns suggested the presence of weak and moderate basic sites in all catalysts, indicating phase transformation due to the decomposition, in situ, of as-prepared nanotubes. The catalyst NiTNT exhibited the highest CO2 and methane conversion at 600 ÂC, with about 43 and 25%, respectively, and H2/CO ratio equal 1, without deactivation over time. PtTNT was lesser susceptible to coking, although sintering remarkably decreased the performance of this solid. On the other hand, PtTNT and CoTNT showed formation of coke over the PtOx/PtTiO3 and Co0/CoTiO3 active phase, respectively, so that the latter solid deactivated during the dry reforming of methane. / A reaÃÃo da reforma seca do metano foi conduzida na presenÃa de nanotubos de titanatos (TNTs) modificados com Co, Ni e Pt. Os TNTs foram sintetizados via tratamento hidrotÃrmico e, posteriormente, foram submetidos à troca iÃnica por Ni e Co, utilizando soluÃÃes de nitrato hexahidratado, ou foram submetidos à impregnaÃÃo via-Ãmida com soluÃÃo de H2PtCl6.6H2O (1% m/m de Pt). Os catalisadores foram caracterizados antes e apÃs reaÃÃo de reforma seca do metano por anÃlise quÃmica (CHN), difraÃÃo de raios-X (DRX), espectroscopia Raman, isotermas de adsorÃÃo-dessorÃÃo de nitrogÃnio, reduÃÃo termoprogramada (TPR), dessorÃÃo termoprogramada de CO2 (TPD-CO2), microscopia eletrÃnica de transmissÃo (TEM), microscopia eletrÃnica de varredura (MEV-EDS) e espectroscopia fotoeletrÃnica de raios-X (XPS). Os resultados de Raman e DRX evidenciaram a presenÃa da fase Na2Ti3O7 para os nanotubos sÃdicos, enquanto que para os nanotubos modificados foram identificados picos e modos vibracionais referentes Ãs fases CoTi3O7, NiTi3O7 e PtOx/Na2Ti3O7. As imagens de TEM exibiram morfologia tubular composta por multiparedes, corroborando com os resultados de DRX e Raman. Os resultados de MEV-EDS mostraram a composiÃÃo dos nanotubos com razÃo M/Ti menor que o teÃrico (0,33), devido à presenÃa de Ãgua estrutural. Os resultados de XPS confirmaram a existÃncia da fase M(OH)2 (M=Co, Ni ou Pt) presentes na superfÃcie dos nanotubos. As curvas de TPR sugeriram a formaÃÃo da fase M0/MTiO3 (M = Co, Ni e Pt), apÃs a reduÃÃo dos nanotubos a 650 ÂC. As isotermas de adsorÃÃo-dessorÃÃo de nitrogÃnio dos TNTs sÃdicos e modificados apresentaram isotermas do tipo IV com estrutura essencialmente formada por mesoporos. Os perfis de TPD-CO2 sugeriram a presenÃa de sÃtios bÃsicos fracos e moderados em todos os catalisadores, indicando mudanÃa de fase devido à decomposiÃÃo in situ dos nanotubos como sintetizados. O catalisador NiTNT apresentou os melhores resultados de conversÃo de CO2 e metano a 600 ÂC, com aproximadamente 43 e 25%, respectivamente, e razÃo H2/CO igual a 0,5, sem desativaÃÃo ao longo do tempo. PtTNT foi menos susceptÃvel à formaÃÃo de coque, embora o fenÃmeno de sinterizaÃÃo tenha desfavorecido o desempenho do sÃlido. Por outro lado, os sÃlidos PtTNT e CoTNT apresentaram formaÃÃo de coque sobre as fases ativas PtOx/PtTiO3 e Co0/CoTiO3, respectivamente, de modo que este Ãltimo sÃlido desativou durante a reaÃÃo da reforma seca do metano.
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