Diss. (sammanfattning) Linköping : Univ., 2004. / I publikationen felaktig serie: Linköping studies in health sciences. Härtill 4 uppsatser.

De nos jours, les produits chimiques toxiques industriels ne sont pas toujours traités proprement, et leurs contaminants peuvent directement affecter la sécurité de l'eau potable. La photocatalyse, «une technologie verte» est une approche efficace et économique qui joue un rôle important dans la conversion de l'énergie solaire et la dégradation des polluants organiques. Ce manuscrit de thèse rapporte sur le développement des matériaux avancés (basés sur TiO2 et ZnO) susceptibles d'exploiter l'énergie solaire renouvelable pour résoudre les problèmes de pollution environnementale. Une partie de ce travail a été consacrée pour l’amélioration de l’activité photocatalytique du TiO2 sous lumière UV et visible. Par conséquent, les nanofibres composites de rGO/TiO2, BN/TiO2 et BN-Ag/TiO2 ont été élaborées en utilisant la technique d'électrofilage (electrospinning). La deuxième partie porte sur le ZnO, ainsi que les nanotubes multi co-centriques de ZnO/ZnAl2O4 et les nanotubes de ZnO dopés Al2O3 qui ont été synthétisés en combinant les deux techniques : dépôt de couche atomique (ALD) et electrospinning. Les propriétés morphologiques, structurelles et optiques de toutes les nanostructures synthétisées ont été étudiées par différentes techniques de caractérisations. Les résultats ont montré que les propriétés chimiques et physiques ont un effet très important sur les propriétés photocatalytiques des matériaux synthétisés. En outre, il a été constaté que l'effet de dopage conduit à une séparation de charge efficace dans le photocatalyseur, ce qui rend l’activité photocatalytique plus efficace. De plus, le méthyle orange et le bleu de méthylène ont été utilisés comme modèle de référence. Une amélioration significative et une stabilité à long terme de l’activité photocatalytique ont été observées avec les matériaux dopés comparés aux matériaux non-dopés sous lumière UV et visible. Des tests antibactériens contre Escherichia coli ont été également effectués; les résultats indiquent que BN-Ag/TiO2 présente à la fois des propriétés photocatalytiques intéressantes pour la dégradation des composés organiques et pour l'élimination des bactéries. / Nowadays, industrial toxic chemicals are still not properly treated and these contaminants may directly impact the safety of drinking water. Photocatalysis “a green technology” is an effective and economical approach and plays an important role in solar energy conversion and degradation of organic pollutants. This thesis manuscript reports on developing advanced materials (based on TiO2 and ZnO) being capable of exploiting renewable solar energy for solving the environmental pollution problems. A part of this work was dedicated to improve the UV and visible light TiO2 photoresponse. Therefore, rGO/TiO2, BN/TiO2 and BN-Ag/TiO2 composties nanofibers were successfully elaborated using the electrospinning technique. The second part focused on ZnO. Novel structures of ZnO/ZnAl2O4 multi co-centric nanotubes and Al2O3 doped ZnO nanotubes were designed by combining the two techniques of atomic layer deposition (ALD) and electrospinning. The morphological, structural and optical properties of all synthesized nanostructures were investigated by several characterization techniques. The results show that the chemical and physical properties have a high impact on the photocatalytic properties of the synthesized materials. Moreover, it was found that the doping effect lead to a more efficient charge separation in the photocatalyst, which is an advantage for photocatalytic activities. In addition, methyl orange and methylene blue were used as model reference. A significant enhancement and a long-term stability in the photocatalytic activity were observed with the doped materials compared to the non-doped ones under both UV and visible light. Antibacterial tests against Escherichia coli have also been performed; the results indicate that BN-Ag/TiO2 present interesting photocatalytic properties for both organic compound degradation and bacterial removal.

Orientador: Diogo Paschoalini Volanti / Resumo: O avanço na ciência e tecnologia de sensores de compostos orgânicos voláteis (VOCs) é importante para o desenvolvimento sustentável de materiais funcionais. A dissertação de mestrado refere-se à avaliação do uso de óxido de grafeno (GO, sigla em inglês) em óxido metálicos (OM) tipo-n (V2O5) e tipo-p (Co3O4) para melhorar a sensibilidade, a seletividade e o tempo de resposta dos sensores. O GO teve uma modificação sendo submetido a um processo oxidativo. Os OMs nano ou microestrurados foram preparados a partir de seus sais ou por processos de ressolubilização dos óxidos. Por fim, os compósitos GO-OM foram preparados após os percursores ficarem em suspensão com o GO por 24 horas. O GO aumentou a adsorção gasosa dos compostos resultando em maior seletividade e sensibilidade. Por outro lado, os principais benefícios das estruturas nano e microestrutruradas dos OMs seriam a maior área superficial do material resultando em melhores propriedades gasosas, resultando em mais sítios ativos para adsorção do oxigênio e das moléculas do gás analito. As respostas sensoras foram avaliadas na presença de diferentes concentrações (nas faixas de ppm e ppb) de VOCs (ex.: acetona, acetaldeído, etanol, metanol, benzeno, xileno e tolueno) em atmosfera seca. / Abstract: The advancement in science and technology of volatile organic compounds (VOCs) sensors is essential for the sustainable development of functional materials. The master's thesis refers to the evaluation of the use of graphene oxide (GO) in metallic oxides (OM) type-n (V2O5) and type-p (Co3O4) to improve sensitivity, selectivity and the response time of the sensors. The GO had a modification being subjected to an oxidative process. The nano or microstructured OMs were prepared from its precursors. Finally, the GO-OM composites were prepared after the precursors were in suspension with the GO for 24 hours. The GO increased the gaseous adsorption of the compounds resulting in greater selectivity and sensitivity. On the other hand, the main benefits of the nanostructured and micro-structured structures of OMs would be the greater surface area of the material resulting in better gaseous properties, resulting in more active sites for adsorption of oxygen and analyte gas molecules. The sensory responses were evaluated in the presence of different concentrations (in the ppm and ppb ranges) of VOCs (e.g., acetone, acetaldehyde, ethanol, methanol, benzene, xylene and toluene) in a dry atmosphere. / Mestre

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Copolymers that contain terminal or pendent functional groups have great potential in the biomedical area due to their biocompatibility and tunable properties.1-3 In this research, two vinyl functional epoxides, vinyldimethylsilylpropyl glycidyl ether (VSiGE) and ethoxy vinyl glycidyl ether (EVGE), were synthesized. These heterobifunctional monomers were polymerizable via the epoxide groups and can be functionalized via thiol-ene reactions through the pendent vinyl groups. A series of amphiphilic block copolyethers based on poly(ethylene oxide) and poly(1,2-butylene oxide) that incorporate VSiGE or EVGE were synthesized and characterized. The vinyl ether and vinyl silane functional groups were functionalized after polymerization and the functional polymers formed pH-sensitive micelles in aqueous medium. The copolyethers were loaded with ritonavir yielding well-controlled nanoparticles. Poly(L-glutamic acid) is comprised of naturally occurring L-glutamic acid repeating units that are linked together with amide bonds. In this research, we have prepared magnetic block ionomer complexes based on poly(ethylene oxide)-b-poly(L-glutamic acid) copolymers. This is of interest due to the biocompatibility and biodegradable nature of the poly(L-glutamic acid) component of the backbone. Allyl- and thiol-functional poly(ethylene oxide)-b-poly(L-glutamic acid) copolymers were also synthesized and coated onto the surface of iron oxide nanoparticles. Allyl- and thiol-tipped single particles were reacted with each other to prepare magnetic clusters. Transverse relaxivities of the clusters were found to be significantly higher than that of single particles. One major problem in commercial development of therapeutic proteins is their poor transport across cellular membranes and biological barriers such as the blood-brain barrier (BBB). One solution to this problem is to modify proteins with amphiphilic block copolymers such as PEO-b-PPO-b-PEO, Pluronics®. However, it isn't possible to independently tune the two PEO block lengths with commercial Pluronics® since a difunctional PPO macroinitator is utilized to grow both PEO blocks simultaneously (HO-EOn-b-POm-b-EOn-OH). Another challenge is introducing functional group which allows post-polymerization functionalization for specific applications. In this study, a series of heterobifunctional asymmetric amino-EOn1-b-POm-b-EOn2-OH block copolymers (APs) with different molecular weights of each block were synthesized and the amino terminal group was conjugated to an antioxidant enzyme, Cu/Zn superoxide dismutase (SOD1). The conjugates were characterized and their cellular uptake was investigated. / Ph. D.

Orientador: Valdecir Farias Ximenes / O Programa de Pós Gaduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter institucional e integra as atividades de pesquisa em materiais de diversos campi / Resumo: O óxido de zinco (ZnO) é um semicondutor muito utilizado na área tecnológica, principalmente em dispositivos fotovoltaicos e mais recentemente, vem sendo utilizado em aplicações biomédicas. Porém, citotóxicos, principalmente quando em tramanho nanométrico, associados ao seu uso, não devem ser descartados. Assim, este trabalho teve por objetivo estudar o efeito tempo de sonicação na morfologia de nanopartículas de ZnO e como estas diferenças poderiam afetar a estrutura da albumina, provocar a hemólise de eritrócitos e a ativação de neutrófilos humanos, quando em contato com este material. Amostras de ZnO foi obtido através do método de síntese ultrassônica, caracterizada por métodos ópticos e suas morfologias observadas em microscópio de varredura eletrônica. Foram obtidas duas morfologias distintas: nanoflores e nanoagulhas. Em todo os testes biológicos a concentração final de ZnO foi 0,1mg/mL em todos os experimentos, onde incubou-se o mesmo com albumina humana e com células sanguíneas (eritrócitos e neutrófilos). Não se observou alterações significativas na estrutura da albumina quando incubada com ZnO, como evidencido por estudo de fluorescência intrínseca e extrínseca. Uma exceção foi uma pequena agregação de proteína quando incubada com o ZnO (nanoflor) avaliado por espalhamento de luz (Rayleigh). Embora pouco efetiva, esta morfologia do ZnO também foi mais eficaz na indução de hemólise de eritrócitos (22%), se comparado às nonoagulhas (11%), após 48 horas de reação (controle negativo=3,7%). A mesma tendência foi observada para estimulação de neutrófilos avaliada por luminol (nanoflores 26,9%, nanoagulhas 8,9% e controle negativo=8,7%). Em conclusão, podemos afirmar que ZnO nanoestruturado apresentou baixa toxicidade nos modelos aqui estudados, o que reforça a sua potencial aplicação in vivo / Abstract: Zinc oxide (ZnO) is a semiconductor that has been highly explored in multiple areas of science, especially in photovoltaic devices and, more recently, in biomedical aplications. However, the cytotoxic effects, especially in nanosize, associated with its use cannot be ruled out. Therefore, this work aimed to study how the sonication time can influence the morphology obtained for the zinc oxide and how these diferrences could affect the structure of albumin, cause hemolysis of erythocytes and activation of human neutrophils. ZnO was obtained by ultrasonic synthesis method and characterized by optical methods and their morphologies observed in scanning electron microscope. Two differents morphologies were obtained: nanoflowers and nanoneedle. ZnO was incubated with human serum albumin and blood cells (erytrocytes and neutrophils) in final concentration of 0.1mg/ml. The results showed no significant modification in albumin structure when incubated with ZnO, evidenced by intrisic and extrinsic fluorescence studies. One exception was a small protein aggregation observed in light scattering (Rayleigh). Although somewhat effective, this morphology of ZnO was also more effective at inducing hemolysis of erythrocytes (22%) compared to nanoagulhas (11%), after 48 hours of reaction (negative control = 3.7%). The same trend was observed for stimulation of neutrophils measured by luminol (nanoflowers 26.9% and nanoneedle 8.9%) (negative control = 8.7%). In conclusion. It can be said that ZnO nanostructured showed low toxicity in the models studied, which reinforces the in vivo applications / Mestre

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Call number: LD2668 .T4 1965 K21 / Master of Science

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