Le Traité d'Interdiction Complete des Essais nucléaires (TICE) met en oeuvre des moyens de détection d'essais nucléaires au sein d'un système de surveillance international (SSI). Le Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA) a développé, dès le milieu des années 90, le système SPALAX (Système de Prélèvement d'Air en Ligne avec l'Analyse des radioXénons). L'analyse du xénon, y compris les isotopes radioactifs issus de la réaction de fission lors de l'explosion, requiert le développement de procédés très performants pour la concentration de celui-ci. Dans ces travaux de thèse, les phénomènes d'adsorption et de diffusion du xénon sont étudiés dans une zéolithe ZSM-5 échangée à l'argent. Le couplage « expérience/simulation Monte-Carlo » est mis à profit pour déterminer les données thermodynamiques essentielles sur l'adsorption des gaz rares et pour caractériser les sites d'adsorption. La présence d'un site fort d'adsorption, identifié comme étant des nanoparticules d'argent et intervenant à faible concentration de gaz rares (notamment pour le xénon et le radon) dans certaines zéolithes échangées à l'argent, permet d'atteindre des performances d'adsorption et de sélectivité à ce jour inégalées. Ces résultats permettent d'envisager leur utilisation pour de nombreuses applications cruciales dans le domaine de la capture et de la séparation des gaz rares : production industrielle de gaz rares, retraitement des gaz issus du combustible irradié, dépollution de l'air en radon / The Comprehensive Nuclear-Test-Ban Treaty (CTBT) implements means for detecting nuclear tests in an International Monitoring System (IMS). The Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA) has developed in the mid-90s, the SPALAX system (Système de Prélèvement d’Air en Ligne avec l’Analyse des radioXénons). Xenon analysis, including radioactive isotopes from the fission reaction during the explosion, requires the development of highly efficient process for xenon concentration. In this work, the adsorption and diffusion phenomena of noble gases are studied in silver exchanged ZSM-5 zeolite. The "experience / Monte Carlo simulation" coupling is used to determine the essential thermodynamic data on the adsorption of noble gases and to characterize the adsorption sites. The presence of a strong adsorption site, identified as silver nanoparticles and intervening at low concentration of noble gases (including xenon and radon) in some silver exchanged zeolites, achieves adsorption and selectivity performance to date unrivaled. These results allow considering their use in many critical applications in the field of capture and separation of rare gases: rare gas industrial production, reprocessing of spent fuel from gas, radon in air pollution control

Silver nanoparticles (AgNPs) containing consumer products have increasingly emerged in the market because of their potential antibacterial property, which might result in increased human exposure and environmental contamination. AgNPs are toxic to mammalian and other cells but the determinants of this toxicity remain to be fully characterised and the potential impact of DNA repair systems has been poorly explored. This study, therefore, examined to what extent the size and shape of synthesised AgNPs determined AgNP toxicity in DNA repair proficient and deficient (8-oxoguanine DNAglycosylase; WT and OGG1-/-, respectively) mouse embryonic fibroblasts (MEFs) as well as a well-known human cell line used in the toxicity testing, HepG2 cells. Citrate-stabilised spherical- and triangular-shaped AgNPs (S-AgNPs andT-AgNPs, respectively) were synthesised chemically from AgNO3 using combinations of NaBH4 and sodium citrate as a reducing and stabilising agent, respectively, and purified by dialysis. Three different sized S-AgNPs were prepared with diameters of 7.6 ± 1.2, 14.3 ± 4.2, and 52.5 ± 17.9 nm as measured using transmission electron microscope (TEM), and their zeta potentials were -36.1±2.7, -39.5±2.7 and -36.7±4.1 mV, respectively. T-AgNPs had an edge length and thickness of 71.4 ± 11.1 nm and 5.7 ± 0.8 nm, respectively. The size and zeta potential of the purified AgNPs were constant in distilled water for at least 6 months. The uptake of both S- and T-AgNPs by cells resulted in a time and dose-dependent increase in the number of cellular AgNPs and the amount of Ag+ released intracellularly. These increases were associated with a decrease in cell viability (as measured using the MTT assay) and cell survival (the clonogenic assay), and an induction in ROS generation (the DCF assay) and DNA damage(the alkaline Comet assay) for all three cell lines. AgNPs were observed in cells using TEM, suggesting the uptake of AgNPs via an endocytosis pathway. Results suggested that an increase in cellular AgNP level and intracellular released Ag+ content were associated with a time and dose-dependent toxicity. Interestingly, cellular AgNP level and intracellular released Ag+ content might play an important role in size-dependent AgNP toxicity, in which exposure to the smaller S-AgNP sizes (7nm and 14nm) resulted in higher levels of both cellular AgNPs and Ag+ released intracellularly, and then to increased toxicity when compared with the larger S-AgNP size (50nm). Moreover, different shaped AgNPs might induce toxicity by different mechanisms: ROS-mediated toxicity might be induced by both 70nm T-AgNPs and 50nm S-AgNPs and 70nm T-AgNPs might also induce cell membrane damage. AgNP-induced toxicity was different in different cell lines with HepG2 cells being more sensitive to AgNPs particularly using the clonogenic assay, and this toxicity was associated with higher DNA damage observed in HepG2 cells after 24 h. OGG1-/- MEFs were more sensitive to intracellular released Ag+, leading to higher ROS formation and DNA damage in OGG1-/- MEFs than that observed in WT MEFs. In summary, this study strongly suggests that AgNPs induce toxicity via a Trojan-horse type mechanism, and not only Ag+ released intracellularly but also cellular AgNPs take part in this toxicity, and will eventually result in the biological responses of the cells.

Orientadores: Carlos Rettori, Pascoal José Giglio Pagliuso / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-22T06:56:36Z (GMT). No. of bitstreams: 1 Lesseux_GuilhermeGorgen_M.pdf: 14003739 bytes, checksum: b737fc7f0d847cdc75e895351974e1e2 (MD5) Previous issue date: 2013 / Resumo: Compostos nanoestruturados têm atraído cada vez mais atenção do ponto de vista tecnológico devido às inúmeras possibilidades em termos de aplicação nas mais diversas áreas. Além da motivação em termos de aplicação, o aumento da proporção de átomos na superfície em relação ao volume e a redução da dimensionalidade nestes compostos trazem consigo novas questões em física. Com base nisso, o estudo científico sistemático destas questões é fundamental para o desenvolvimento da nanociência e da nanotecnologia de forma geral. No presente trabalho são estudadas propriedades magnéticas de três tipos de nanopartículas (NPs): i) NPs de Au assistidas por óxidos do tipo R2O3 (R = Er e Y) que exibem propriedades ferromagnéticas; ii) NPs metálicas, Au e Ag, com a impureza magnética Er3+ diluída permitindo assim a sondagem microscópica de propriedades físicas por Ressonância de Spin Eletrônico; iii) E, por fim, NPs de NaYF4 mono e codopadas com os íons de terras raras RE = Yb3+, Er3+ e Tm3+ nas quais foi possível verificar o fenômeno de upconversion. Com base em adaptação de métodos estabelecidos na literatura, [1_3] foi desenvolvida uma rota química para a obtenção de NPs de Au com propriedades ferromagnéticas acentuadas pela incorporação de óxidos. A partir da magnetização de saturação em 2 K e baseado em uma análise termogravimétrica (TGA) estimou-se um momento magnético efetivo de aproximadamente 0.2 µB por átomos de Au na superfície das NPs. Além da caracterização magnetometrica típica, observou-se uma linha intensa de ESR em banda-X desde 370 K até 4.2 K. Esta ressonância possui intensidade praticamente constante caracterizando a ressonância observada como ferromagnética (FMR). Estes resultados são interpretados com base na ligação entre a capa orgânica (capping), o óxido R2O3 e os átomos de Au gerando uma hibridização efetiva dos orbitais 5d-6s dos elétrons do Au. Esta hibridização seria, então, responsável por tornar a camada 5d do Au magnética devido a spins não compensados nos orbitais 5d. As NPs metálicas com impurezas de Er3+ foram obtidas por uma variação do método utilizado para as NPs de Au ferromagnéticas. Os valores de g e as estruturas hiperfinas observadas indicam que o íon Er3+ está em um sítio cúbico tanto nas partículas de Ag como nas de Au. Os espectros de ESR mostram que não há deslocamento de g e relaxação tipo Korringa devido à interação de troca entre os spins do Er3+ e os dos elétrons de condução, sugerindo assim que esta interação de troca não ocorre em NPs metálicas. Por fim, as NPs de NaYF4 dopadas com RE = Yb3+, Er3+ e Tm3+ foram obtidas por um método estabelecido na literatura. [4, 5] A incorporação, o estado de oxidação e a concentração dos íons magnéticos Er3+ e Yb3+ foram confirmados por medidas de magnetização dc e de ESR. Observou-se emissão visível no verde e no azul para amostras codopadas com 20%Yb3+ / 2%Er3+ e 30%Yb3+ / 0.5%Tm3+, respectivamente, devido ao fenômeno conhecido como upconversion / Abstract: Nanostructured compounds have attracted growing attention from the technological point of view due to numerous possibilities in terms of application in several areas. Besides, the large surface/volume atoms ratio and the reduced dimensionality of these nanocompounds raised new fundamental physical issues. Therefore, a detailed and systematic scientific study regarding these phenomena is crucial for the sake of nanoscience and nanotechnology development. In this dissertation, we thoroughly investigated the magnetic properties of three different types of nanoparticles (NPs): i) Au NPs assisted by oxides R2O3 (R = Er and Y) which present unexpected ferromagnetic properties; ii) diluted magnetic Er3+ impurities in Ag and Au NPs, which allow Electron Spin Resonance to study several microscopic local physical properties and, finally, iii) single and co-doped Yb3+, Er3+ and Tm3+ NaYF4 NPs that allowed to verify the up-conversion phenomena in these NPs. After adapting and improving already established methods reported in the literature, [1_3] we developed a novel chemical route to obtain Au-NPs with enhanced ferromagnetic properties by oxide incorporation. Based on the saturation magnetization at 2 K and thermogravimetric analysis (TGA), we estimated an effective magnetic moment of µeff ¿ 0.2 µB per Au atom on the surface of the NPs. Besides the typical magnetometric characterization, we also carried out X-band ESR experiments. An intense ESR line was observed in the range of 4.2K = T = 370K with an integrated signal intensity which is almost constant in the entire T-range. Based on our results, the observed ESR signal is attributed to a ferromagnetic resonance (FMR). These results are discussed in terms of bonds between the NP-capping ligands and the Au atoms, which give rise to an effective hybridization between the 5d-6s electrons at the surface of the AuNPs. This hybridization might be the responsible mechanism for the Au 5d shell to become magnetic due to uncompensated spins in the 5d orbitals. The metallic Er3+ doped Ag and Au NPs were obtained by a slightly modified method used to get the ferromagnetic Au -NPs. The ESR g-values and observed hyperfine splitting indicate a cubic symmetry for the Er3+ ions in the Ag and Au NPs. Furthermore, we observed no g-shift and Korringa relaxation due to the exchange interaction between the magnetic rare-earth impurities and the conduction electron spins. This fact suggests that such an exchange interaction is negligible in metallic NPs. Finally, the Er3+, Yb3+ and Tm3+ doped NaYF4 NPs were obtained by a method already established in the literature. [4, 5] The incorporation of the Er3+ and Yb3+ ions as well as their oxidation state and concentration were confirmed by T-dependent magnetization and ESR measurements. For the co-doped NaYF4 NPs, we observed by naked eye the expected green and blue emitted lights of Yb/Er and Yb/Tm, respectively, due to a phenomenon known as upconversion / Mestrado / Física / Mestre em Física

Orientadores: Patrícia da Silva Melo, Priscyla Daniely Marcato Gaspari / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-22T07:03:53Z (GMT). No. of bitstreams: 1 DePaula_LarissaBarbosa_M.pdf: 38500312 bytes, checksum: 3a0fd9c71b979fe937cf40664c0df057 (MD5) Previous issue date: 2013 / Resumo: Queimaduras representam um problema de saúde pública, gerando um gasto anual de cerca de R$ 55 milhões ao Sistema Único de Saúde (SUS). Os produtos destinados ao tratamento de queimaduras são em sua grande maioria importados, tornando relevantes estudos que visem ao desenvolvimento de materiais com características adequadas ao tratamento e produzidos a partir de matérias-primas de baixo custo e fácil obtenção. O objetivo deste trabalho foi avaliar os possíveis efeitos tóxicos e o potencial de cicatrização de S-Nitrosoglutationa (GSNO) encapsulado em nanopartículas poliméricas (alginato-quitosana e poli (?-caprolactona) (PCL) recobertas por quitosana) e de nanopartículas de prata (AgNPs). O GSNO foi sintetizado através de reação de S-Nitrosação direta de glutationa e caracterizado por espectrofotometria. As nanopartículas de alginato-quitosana (AG/CS) contendo GSNO foram preparadas através do método de gelificação iônica. As nanopartículas de PCL recobertas por quitosana (PCL/CS) e contendo GSNO foram preparadas através do método de dupla emulsão (água/óleo/água) e evaporação do solvente. Ambas as nanopartículas foram caracterizadas por espectroscopia de correlação de fótons (ECF) e microscopia eletrônica de varredura (MEV). As AgNPs foram produzidas extracelularmente por método biotecnológico utilizando-se o fungo Fusarium oxysporum e caracterizadas por ECF e microscopia eletrônica de transmissão (MET). A toxicidade in vitro das nanopartículas foi avaliada através de ensaios de citotoxicidade utilizando-se cultura de células de linhagens pré-estabelecidas e o potencial de cicatrização foi avaliado através de indução de queimadura térmica em ratos Wistar machos, os quais foram posteriormente eutanaziados para avaliação da toxicidade in vivo das nanopartículas. As AG/CS contendo GSNO apresentaram diâmetro médio de 321,0 ± 12,2 nm e potencial Zeta de +37,6 ± 0,6 mV. As PCL/CS contendo GSNO apresentaram-se esféricas, com diâmetro médio de 448,6 ± 35,38 nm e potencial Zeta de +23,11 ± 4,75 mV. As AgNPs apresentaram-se esféricas e altamente estáveis, com diâmetro médio de 7,3 ± 3,0 nm e potencial Zeta de -31,1 ± 2,09 mV. As nanopartículas apresentaram-se pouco tóxicas in vitro e in vivo. O tratamento das lesões com as nanopartículas reduziu a área lesionada em praticamente 100% após 35 dias, diminuindo o tempo necessário para a diferenciação de fibroblastos em miofibroblastos, e revertendo o processo inflamatório mais rapidamente. Nossos resultados indicam que os sistemas nanoparticulados estudados podem fornecer uma nova e eficaz direção terapêutica para o tratamento de queimaduras / Abstract: Burn injuries represent a public health problem, generating an annual cost of about R$ 55 million to the Brazilian Unified Health System. The products for the treatment of burns are mostly imported, so studies aimed at developing materials with appropriate characteristics to the treatment and produced from cheap raw materials and easily obtained are relevant. The aim of this study was to evaluate the possible toxic effects and healing potential of S-Nitrosoglutathione (GSNO) encapsulated in polymeric nanoparticles (alginate-chitosan and chitosan-coated poly (?-caprolactone) (PCL)) and silver nanoparticles (AgNPs). GSNO was synthesized by direct S-Nitrosation reaction of glutathione (GSH) and characterized by spectroscopic analysis. Alginate-chitosan nanoparticles (AG/CS) loaded with GSNO were prepared through ionic gelation method. Chitosan-coated PCL nanoparticles (PCL/CS) loaded with GSNO were prepared by the double emulsion method (water/oil/water) and solvent evaporation. Both of the nanoparticles were characterized by dynamic light scattering (DLS) and scanning electron microscopy (SEM). AgNPs were produced extracellularly by a biotechnological method using the fungus Fusarium oxysporum and characterized by DLS and transmission electron microscopy (TEM). The in vitro toxicity of the nanoparticles was assessed through cytotoxic assays using cell culture of predetermined strains and healing potential was evaluated through thermal burn induced in male Wistar rats, which were subsequently euthanized for evaluation of the in vivo toxicity of the nanoparticles. AG/CS loaded with GSNO had an average diameter of 321.0 ± 12.2 nm and Zeta potential of +37.6 ± 0.6 mV. PCL/CS loaded with GSNO were spherical, with an average diameter of 448.6 ± 35.38 nm and Zeta potential of +23.11 ± 4.75 mV. AgNPs were spherical and highly stable, with an average diameter of 7.3 ± 3.0 nm and Zeta potential of -31.1 ± 2.09 mV. The nanoparticles were slightly toxic in vitro and in vivo. The treatment of the burns with the nanoparticles reduced the burned area in almost 100% after 35 days, decreasing the required time for fibroblasts differentiation into myofibroblasts, and reversing the inflammatory process faster. Our results showed that the studied nanoparticulated systems may provide a novel and effective therapeutic direction for the treatment of burn injuries / Mestrado / Bioquimica / Mestra em Biologia Funcional e Molecular

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-04-19T15:38:52Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese Sérgio Rocha para Defesa OK.pdf: 3444360 bytes, checksum: da9ca3f2c9d898e60430ef1b21bd681a (MD5) / Made available in DSpace on 2016-04-19T15:38:52Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese Sérgio Rocha para Defesa OK.pdf: 3444360 bytes, checksum: da9ca3f2c9d898e60430ef1b21bd681a (MD5) Previous issue date: 2015-02-25 / O infarto agudo do miocárdio (IAM) representa hoje um dos maiores problemas de saúde mundial prevalecendo sobre doenças como câncer, AIDS e doenças respiratórias. Em virtude da relevância, métodos cada vez mais eficientes para auxilio no diagnóstico do IAM vem sendo desenvolvidos. Um destes métodos, os aptassensores, chegam como ferramenta analítica alternativa para detecção de marcadores de necrose miocárdica. Neste trabalho um aptassensor simples e livre de marcação foi desenvolvido para detecção de troponina T cardíaca (cTnT), para isto, nanopartículas de prata foram sintetizadas eletroquimicamente sobre eletrodos impressos de tinta de carbono. Em seguida, 5 μL de cisteína foi adicionada à superfície sensora com intuito de servir de braço químico e possibilitar a imobilização do aptâmero. O aptâmero usado consiste em DNA fita simples modificado com grupos amino (NH2-ssDNA) e específico para o analito em questão. As condições ideais para imobilização do aptâmero e reconhecimento da molécula alvo, assim como a caracterização eletroquímica do aptassensor, foram investigados através das técnicas de voltametria cíclica (CV) e voltametria de pulso diferencial (DPV). A especificidade do aptassensor foi investigada utilizando para isso moléculas alvo específicas e inespecíficas. O reconhecimento do alvo apresentou alta sensibilidade com limite de detecção em 0,1 ng mL−1 de cTnT e uma boa reprodutibilidade (CV = 4%). O sensor também foi testado com amostras de soro humano, apresentando ótima concordância (95% de nível de confiança) com o padrão ouro, o método ECLIA. Neste trabalho pôde-se constatar que as nanopartículas de prata incorporadas a superfície eletródica melhoraram a reprodutibilidade, a condutividade e, consequentemente a resposta sensora, enquanto os aptâmeros asseguraram a sensibilidade e especificidade do aptasensor, apresentando, este modelo, grande potencial para uso no monitoramento dos níveis séricos de troponina cardíaca. / Acute myocardial infarction (AMI) it is one of the most serious diseases in the world responsible for approximately 17 million of deaths in 2012. Therefore, early diagnosis and prompt medical response are of paramount importance for patient survival. Aptasensors can be an alternative, which in combination with electrochemical techniques can provide the simplicity and speed required. A simple and sensitive label-free aptasensor for cardiac troponin T (cTnT) detection was successfully developed. For this purpose, it was chosen a DNA aptamers modified with amino group (NH2-ssDNA) specific to bind cTnT with a high specificity and stability. Herein, silver nanoparticles electrochemically synthesized and cysteine were used to modify the electrode, providing binding sites for aptamer immobilization. The optimum conditions for immobilization of the aptamer and target recognition were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) technique. The aptasensor achieved a low limit of detection (0.3 ng mL−1) and a linear range between 0.1 and 10 ng mL−1 cTnT, significant for acute myocardial infarction diagnosis. Good reproducibility was obtained by the proposed aptasensor supported by a coefficient of variation of 4%. The silver nanoparticles incorporated to the electrode surface improved the reproducibility, while the aptamer secured the sensitivity of the biosensor. The sensor was also tested for human serum samples presenting a good agreement with the ECLIA methods at 95% confident level. This point-of-care approach presents a great potential for use in several situations releasing the aptasensor for use in the cardiac troponin detection.

Orientador: Marcelo Bispo De Jesus / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-27T02:58:56Z (GMT). No. of bitstreams: 1 Ferreira_LuizAlbertoBandeira_M.pdf: 6087254 bytes, checksum: 800e7d6dd948a9f1da84d37dbff2a96d (MD5) Previous issue date: 2015 / Resumo: A nanomedicina se tornou uma promessa de profundos impactos para a saúde humana através da utilização de nanopartículas, nanorobôs e outros nanomateriais para prevenir, diagnosticar ou curar doenças. Um dos exemplos de nanomateriais empregados na medicina são as nanopartículas de prata, que podem ser adquiridas por métodos químicos ou biossintéticos. As nanopartículas de prata apresentam alta atividade antimicrobiana, propriedade essa de grande interesse científico-industrial. Em vista disso, cresce também a preocupação em relação ao uso, manipulação e eliminação desse nanomaterial, visando uma aplicação mais segura. Diante dessas informações, o presente trabalho teve como objetivo investigar mecanismos moleculares envolvidos na citotoxicidade e processamento das nanopartículas biossintéticas de prata em macrófagos peritoneais obtidos de camundongos C57BL/6. Inicialmemte, demonstrando que as nanopartículas atingiram o IC50 de 25 µM em 6h de tratamento por redução do MTT. A análise de microscopia de fluorescência revelou alterações na integridade de membrana a partir de 3 h, que foram agravadas após 6 h de tratamento. Esse mesmo perfil foi observado por microscopia eletrônica de varredura, no qual revelou que após 3 h de tratamento as células já apresentavam perda de projeções celulares, e após 6 h início de fragmentação celular. Além disso, as nanopartículas causaram aumento dos níveis de espécies reativas de oxigênio e demonstramos que este é um fator determinante para os efeitos citotóxicos. Com a inibição da fagocitose e endocitose mediada por caveolina evidenciamos a reversão parcial da citotoxicidade das nanopartículas. Por outro lado, o aumento do efeito citotóxico das nanopartículas também foi observado com a inibição da autofagia, o que sugere que esses processos estejam envolvidos no processamento das nanopartículas. Por fim, concluímos que as nanopartículas biossintéticas de prata apresentaram um efeito citotóxico semelhante aqueles descritos em literatura pelas nanopartículas de síntese química / Abstract: Nanomedicine became a promise of profound impacts on human health through the use of nanoparticles, nanorobots and other nanomaterials to prevent, diagnose or cure diseases. One example of nanomaterials used in medicine is silver nanoparticles, which can be produced by chemical or biosynthetic methods. Silver nanoparticles have high antimicrobial activity; this property is of great scientific and industrial interest. Consequently, there is growing concern about the use, handling and disposal of nanomaterials, aiming more secure application. Hence, the present study aimed to investigate the molecular mechanisms involved in cytotoxicity and intracellular processing of biogenic silver nanoparticles in peritoneal macrophages from C57BL/6 mice. We began showing that the nanoparticles have reached the IC50 of 25 µM after 6 hours of treatment determined by MTT reduction. Fluorescence microscopy analysis showed changes in membrane integrity after 3 h, which has been intensified after 6 h of treatment. A similar profile was observed by scanning electron microscopy, which showed loss of cellular projections after 3 h of treatment and after 6 h was observed cellular fragmentation. In addition, the nanoparticles treatment increased levels of reactive oxygen species and this response seems to be determining for the cytotoxic effects. The inhibition of phagocytosis and caveolin-mediated endocytosis led to a reduction in cytotoxicity of nanoparticles. On the other hand, an increase in the cytotoxic effect was observed upon inhibition of autophagy, suggesting that this response is part of the intracellular processing of the nanoparticles in peritoneal macrophage. Finally, we concluded that the biogenic of silver nanoparticles exhibited cytotoxic effects similar to that described for silver nanoparticles chemically synthesized / Mestrado / Fármacos, Medicamentos e Insumos para Saúde / Mestre em Ciências

Orientadores: Francisco das Chagas Marques, Carlos Lenz César / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-29T22:06:44Z (GMT). No. of bitstreams: 1 VillegasBorrero_NelsonFabian_M.pdf: 7427305 bytes, checksum: 95d120bd4cca81a54f7e8af57dfd2ab5 (MD5) Previous issue date: 2015 / Resumo: Neste trabalho foram fabricadas nanopartículas metálicas de prata (NPsM de Ag) em soluções coloidais usando a técnica de ablação à laser. Parâmetros como o comprimento de onda do laser, energia do pulso e a taxa de repetição afetam a distribuição de tamanho das NPsM. Assim, neste trabalho estudamos a influência destes parâmetros sobre o tamanho das NPsM de Ag. Para isto foi feita uma montagem experimantal na qual um alvo de prata é imerso em um líquido e irradiado por um pulso de laser de Nd:YAG para criar soluções coloidais. Foi encontrada uma variação dos picos de absorção entre = 394nm e = 405nm. Segundo a previsão da teoria de Gustav Mie, as variações nos picos tem a ver com a variação na distribuição de tamanhos. Para comprovar estes resultados foi feita uma estimativa do tamanho médio das NPsM de Ag usando a análise de imagens tomadas com o Microscópio Eletrônico de Varredura (MEV) e a técnica de Espalhamento Dinâmico da Luz (DLS). O espectro experimental e a teoria de Gustav Mie (simulação feita usando o software mathematica) encontram-se em concordância. As NPsM produzidas foram usadas para medir o efeito de aumento no sinal Raman em superfícies (SERS) encontrando-se que o sinal do espalhamento Raman de corantes usados em diferentes pesquisas (Rodâmina B e N719) aumenta com o uso das NPsM / Abstract: In this work we fabricated silver nanoparticles (Ag NPs) in colloidal solutions with specific sizes. Parameters like laser wavelength, pulse energy and pulse repetition rate affect the distribution of NPs size. In this work we studied the influence of these parameters on the size of Ag NPs. For that purpose we mount a set-up in which a silver target was immersed in liquid and irradiated by Nd:YAG pulsed laser to create different colloids. We found that the absorption peak of these colloids lays between 394nm and 405nm. We estimated a mean size of Ag NPs from images taken by Scanning Electron Microscope (SEM) and Dynamic Ligth Scattering (DLS). The calculated absorption spectra and simulation through Gustav Mie theory (Simulated in Matthemathica software) were in good agreement. The produced NPs were used in Enhacement Raman Spectroscopy (SERS) measurements, finding that the signal of Rhodamina B and N719 Dyes increases using these NPsM / Mestrado / Física / Mestre em Física / 1247650/2013 / CAPES

Orientador: César Renato Foschini / Resumo: O óxido de zinco (ZnO) apresenta uma grande versatilidade física, elétrica, mecânica e propriedades químicas que podem ser exploradas em uma variedade de aplicações, tais como fotocatálise, nanoadsorventes e sensoriamento de gases. Os materiais nanoestruturados têm atraído a atenção da ciência e tecnologia nos últimos anos porque podem melhorar suas propriedades em nanoescala. A prata em escala nanométrica tem gerado interesse de pesquisadores de diferentes áreas, pois a prata é moldável e maleável, possui elevada condutividade térmica e elétrica, além de ser um forte oxidante. Neste trabalho, foram desenvolvidos filmes de óxido de zinco puro e dopados com nanopartículas de prata, visando aplicação em sensores de gás. Os filmes de óxido de zinco foram fabricados pelo método dos precursores poliméricos e utilizados como matriz devido a sua interatividade com os gases. As nanopartículas de prata foram produzidas por meio de reação em emulsão, explorando sua alta condutividade elétrica. Dessa forma, por meio das propriedades de ambos os materiais, desenvolveu-se um sensor de gás composto de óxido de zinco na forma de filmes em substratos de Al2O3, com diferentes camadas dopadas e não dopadas com nanopartículas de prata. Notou-se que o desenvolvimento de um material compósito do tipo filme de ZnO dopado com as nanopartículas de prata, apresentou propriedades melhoradas, como por exemplo, a resposta elétrica do material quando comparada com o filme contendo apenas o filme de ZnO p... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Zinc oxide (ZnO) presents a great physical, electrical, mechanical and chemical versatility that can be exploited in a variety of applications, such as photocatalysis, nanoadsorbents and gas sensing. Nanostructured materials have attracted the attention of science and technology in recent years because they can improve their nanoscale properties. The silver in nanoscale has generated interest of researchers of different areas, because the silver is moldable and malleable, has high thermal and electrical conductivity, besides being a strong oxidant. And this project was developed based on the production of silver nanoparticles and zinc oxide films for the application in gas sensors. The zinc oxide films were manufactured by the method of the polymeric precursors and used as matrix due to its interactivity with the gases. The silver nanoparticles were produced by means of emulsion reaction, exploring their high electrical conductivity. Thus, through the properties of both materials, a gas sensor composed of zinc oxide in the form of films on substrates of Al2O3, with different layers doped and not doped with silver nanoparticles was developed. It was noted that the development of a ZnO film-like composite material doped with the silver nanoparticles exhibited improved properties, such as the electrical response of the material as compared to the film containing only the pure ZnO film. / Mestre

MESHWR / Department of Hydrology and Water Resources / Water borne diseases due to inadequate and unsafe drinking water is a global challenge that has led to a significant number of deaths and illnesses reported annually. These diseases are prevalent in less-developed countries, especially in rural areas where there is shortage of basic infrastructure and inadequate funds for piped water systems in individual households. Community members are forced to resort to collecting water from communal water points and later storing the water in containers for daily use. Recontamination of microbiologically safe drinking water during and after collection from the water source has been recognised as a problem; hence treating water at household level is one way to provide potable water for affected communities. The microbiological quality of household water may be improved by using point-of-use treatment technologies such as chemical disinfection, solar disinfection and ceramic water filters. Some of these technologies are expensive, less effective and difficult to implement in rural communities. This research thus focused on ceramic water filters and finding an appropriate method for silver application so as to produce filters that are effective in both the provision of clean drinking water and the release of silver levels that are safe for human consumption. An assessment of the efficiency of ceramic water filters made with silver nitrate as point-of -use water treatment device in Dertig Village, North West Province, South Africa was carried out. During production of filters made with silver nitrate, the filters undergo firing in an electric kiln and ionic silver is reduced to metallic nanopatches dispersed throughout the porous ceramic media. Both filters made with silver nitrate and conventional silver nanoparticles impregnated ceramic water filters were manufactured at the PureMadi Dertig Ceramic Filter Facility, South Africa. Resulting filters were evaluated and quantified for total coliform and E. coli removal as well as silver concentration in the effluent. Ceramic water filters made with silver nitrate had a high removal efficiency for total coliforms (94.7%) and E. coli (99.3%). A comparison of the performance of filters made with silver nitrate and silver nanoparticles in the provision of potable water was carried out and results showed that the different filters had similar levels of total coliform and E. coli removal, although the silver nitrate filters produced the highest average removal of 97.23% while silver nanoparticles filters produced the lowest average removal of 85.43%. Reasonable silver levels were obtained in effluent from all filters. Average effluent silver levels were 0.07±0.04mg/L, 0.6±1.10 mg/L and 0.8±1.0mg/L for 1 g, 2 g and silver nanoparticle filters, respectively (below the EPA and WHO standard of 100 mg/L). Because silver nitrate filters resulted in the lowest effluent silver concentrations, this could potentially increase the effective life span of the filter. A cost analysis of the process proved that it was cheaper to produce ceramic water filters using silver nitrate as the chemical can be purchased locally and also eliminates labour related costs. Thus, filters made using silver nitrate could potentially improve performance, reduce production costs, and increase safety of production for workers. The results obtained from this study will be applied to improve the ceramic filtration technology as point-of-use water treatment device in an effort to reduce health problems associated with microbial contamination of water stored at household level. / NRF

Boli pripravené kryty rán na bázi prírodných látok polyvinyl alcohol/ hyaluronan/ strieborné nanočastice (PVA/ HA/ Ag-NPs). Hyaluronan bol použitý ako redukčné a stabilizačné činidlo pre syntézu nanočastíc striebra. Pri príprave Ag-NPs boli testované viaceré parametre ako koncentrácia dusičnanu strieborného ako zdroja Ag-NPs (0,01; 0,1;0,5;1 M), koncentrácia kyseliny hyalurónovej (1,2 %) a jej rozdielna molekulová hmotnosť. Kryty rán z nanovlákien boli pripravené pomocou techniky electro-spinning z roztokov líšiacich sa pomerom PVA a HA/Ag-NPs (100; 90/10; 80/20; 60/40; 50/50). Vlastnosti nanokompozitu HA/Ag-NPs boli hodnotené pomocou TEM, reológie, DLS, XRD, UV/Vis spektroskopie a kryty rán boli charakterizované pomocou SEM, TGA, FTIR a ťahovej skúšky.