Devido às características especiais as nanopartículas (10-9m) estão sendo utilizadas em uma ampla gama de produtos, porém é conhecido que a utilização dessas partículas podem causar efeitos biológicos adversos, aumentando a preocupação em relação à saúde e ao meio ambiente. Recentemente, as nanopartículas de prata (AgNPs) têm sido alvo de estudos genotóxicos e citotóxicos, sendo que ainda não existe um consenso acerca da relação entre tamanho e toxicidade dessas partículas. Assim, este trabalho avaliou a citotoxicidade e a genotoxicidade das AgNPs de 10 e 100 nm nas linhagens celulares CHO-K1 e CHO-XRS5, por meio do Ensaios de Viabilidade Celular, Sobrevivência Clonogênica, Teste do Micronúcleo, o Ensaio Cometa e Cinética do Ciclo Celular por Citometria de Fluxo. Em todos os ensaios, as células foram expostas por 24 h à diferentes concentrações de AgNPs (0,025 a 5,0 g/ml) e, as células não tratadas foram utilizadas como controle negativo. A concentração de 5,0 g/ml foi citotóxica nos ensaios de Viabilidade Celular e Sobrevivência Clonogênica, sendo excluída dos ensaios de genotoxicidade. De maneira geral, as células CHO-XRS5 apresentaram menor viabilidade e maior quantidade de danos no DNA do que as células CHO-K1. As AgNPs de 10 nm causaram maiores níveis de danos no DNA em ambas as linhagens e um aumento de células em subG1 logo após o tratamento na linhagem CHO-K1. Entretanto, no tempos 24 e 72 h após o tratamento foi verificada a maior toxicidade (células em subG1) das AgNPs de 100 nm quando comparadas com suas homólogas menores (10 nm). Assim, foi observado que as AgNPs de 10 nm apresentam efeito tóxico a curto prazo similar ou maior do que a mesma concentração de partículas de 100 nm. No entanto, os efeitos genotóxicos e citotóxicos de longo prazo das AgNPs de 100 nm foram maiores do que os da partículas de 10 nm para ambas as linhagens celulares, comprovando que a exposição às AgNPs maiores (100 nm) pode causar mais efeitos biológicos adversos do que suas homólogas menores (10 nm). / Due to their particular characteristics, nanoparticles (10-9m) are being used in a range of products. However, these particles can cause adverse biological effects and because of that, there is a great concern about the health and environmental risks related to the use of these particles. Recently, silver nanoparticles (AgNPs) have been used in a variety of cytotoxicity and genotoxicity studies, but there are still controversies regarding the association between the size and the toxicity of these particles. Thus, in this study, we aimed to evaluate the cytotoxicity and genotoxicity of AgNPS (10 and 100 nm) in two different cell lines, CHO-K1 and CHO-XRS5, by performing Cell Viability assay (XTT), Clonogenic assay, Micronucleus test, Comet assay, as well as by investigating the Cell Cycle kinetics using the flow cytometry. For all the different assays, the cell cultures were exposed for 24 hours to different concentrations of AgNPs (0.025 to 5.0 g/ml) and the untreated cells were used as the negative controls. Since results from the Viability and Clonogenic assays indicated that the concentration of 5.0 g/ml was cytotoxic for both cell lines, this concentration was not included in the genotoxic assays. Our results indicated that the CHO-XRS5 cells presented a lower viability and higher levels of DNA damage compared to the CHO-K1 cells. The 10 nm-AgNPs induced greater levels of DNA damage than the 100 nm-particles in both cell lines and the former also led to a subG1 arrest soon after the treatment only in the CHO-K1 cell line. In contrast, results from all the other assays indicated that greater levels of toxicity were induced by the 100 nm-AgNPs when compared to the 10 nm-particles, both 24 and 72 h after the treatment. Thus, at the same concentration, the short-term effects of the 10 nm-AgNPs were equal to or more toxic than those of the 100 nm-particles. Nevertheless, both long-term genotoxicity and cytotoxicity induced by the 100 nm-AgNPs were greater than those induced by the 10 nm-particles for both cell lines, which suggests that the exposure to greater size particles (100 nm) can cause more adverse biological effects than the exposure to the smaller particles(10 nm).

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-10-02T14:48:12Z No. of bitstreams: 1 marianasilvalopesneves.pdf: 523366 bytes, checksum: 2c33e978d12652cf1b17217fe3509198 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-10-09T19:44:11Z (GMT) No. of bitstreams: 1 marianasilvalopesneves.pdf: 523366 bytes, checksum: 2c33e978d12652cf1b17217fe3509198 (MD5) / Made available in DSpace on 2017-10-09T19:44:11Z (GMT). No. of bitstreams: 1 marianasilvalopesneves.pdf: 523366 bytes, checksum: 2c33e978d12652cf1b17217fe3509198 (MD5) Previous issue date: 2013-04-25 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / A prata é conhecida por sua atividade antibacteriana e tem se mostrado eficiente como alternativa no contexto da resistência bacteriana a drogas, sobretudo na forma de nanopartículas (AgNPs). Nossos objetivos foram a avaliação da susceptibilidade de bactérias representativas contra AgNPs e pesquisa de efeito sinérgico ou antagônico quando associadas a quitosana (QIT) e antimicrobianos de uso terapêutico humano. Foram utilizadas oito linhagens bacterianas de referência, representativas de: Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, S. epidermides e Enterococcus faecalis. O perfil de susceptibilidade foi determinado através do método de microdiluição em caldo, de acordo com as recomendações do CLSI. A concentração inibitória mínima (CIM90) das AgNPs para as amostras testadas foi de 64μg/mL, enquanto que para a combinação AgNPs-QIT foi de 16μg/mL. Considerando-se atividade antimicrobiana somente da QIT, a CIM90 foi de 16 μg/mL. Entre os antimicrobianos testados (meropenem, amicacina, gentamicina, levofloxacina, rifampicina, sulfametoxazol-trimetropim, tetraciclina, e oxacilina e vancomicina, estes apenas para Gram positivos), apesar de a CIM para cada linhagem bacteriana estar de acordo com os valores determinados pelo CLSI observou-se diminuição significativa para todas as drogas testadas quando combinadas com AgNPs-QIT. De modo geral, para todas as espécies bacterianas avaliadas, a associação de AgNPs com QIT ou drogas antimicrobianas apresentaram grande potencial inibitório que pode estar relacionado a estabilidade das AgNPs associadas ao polímero ou a interação positiva das nanopartículas com os antimicrobianos. O ensaio de Checkerboard foi realizado para estabelecer os efeitos sinérgicos ou antagônicos em cada combinação. A possibilidade da interação das AgNPs e da QIT com antimicrobianos já existentes é altamente relevante e reforça as recomendações da literatura acerca da reformulação de uso de antimicrobianos tradicionais, além da pesquisa de novas drogas e estratégias para sobrepujar o crescente fenômeno da resistência bacteriana aos antimicrobianos. / Silver is known for its antibacterial activity and has been shown to be effective as a potential alternative in the context of bacterial resistance to drugs, particularly in the form of nanoparticles (AgNPs). Our objectives were to evaluate the susceptibility of bacteria against AgNPs and representative survey of synergistic or antagonistic when combined with chitosan (QIT) and antimicrobials for human therapeutic use. A total of eight reference strains were evaluated of Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, S. epidermidis and Enterococcus faecalis. The susceptibility patterns were determined by broth microdilution method, according to the CLSI guidelines. The minimum inhibitory concentration (MIC90) of AgNPS to the samples tested was 64μg/mL, while for the combination AgNPs-QIT was 16μg/mL. Considering only antimicrobial activity of QIT, the MIC90 was 16 mg / mL. Among the antimicrobials (meropenem, amikacin, gentamicin, levofloxacin, rifampicin, sulfamethoxazole- trimethoprim, tetracycline, and vancomycin and oxacillin, these only to Gram positive), while the MIC for each bacterial strain is in accordance to the reference CLSI, significant decrease was observed for all tested drugs when combined with AgNPs-QIT. In general, association of AgNPs with QIT or with antimicrobial drugs showed higher inhibitory potential, which may be related to the stability of the polymer associated AgNPs or positive interaction of nanoparticles with antibiotics. The Checkerboard assay was then performed to establish antagonistic or synergistic effects in each combination. The possibility of interaction of AgNPs and QIT with existing antimicrobials is highly relevant and reinforces the recommendations of the literature on the reformulation of traditional antimicrobial use, as well as research into new drugs and strategies to overcome the growing phenomenon of bacterial resistance to antimicrobials.

Orientador: Oswaldo Luiz Alves / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-22T16:53:29Z (GMT). No. of bitstreams: 1 Nascimento_RafaellaOliveirado_D.pdf: 2771988 bytes, checksum: 63b8f98c0da43dba0fe3708e5c13eb94 (MD5) Previous issue date: 2013 / Resumo: A presente tese de doutorado tem como objetivo principal utilizar ferramentas da nanociência e da nanotecnologia para contribuir com a remediação/tratamento de poluentes tradicionais, íons de metais como Pb, Cd, Cu, Co, Ni utilizando como materiais filtrantes folhas de fosfato de cério fibroso (CeP), assim como nanocompósitos inéditos obtidos pela combinação de CeP e nanotubos de carbono de parede múltiplas funcionalizados (MWCNTs- Func) via oxidação (ox-MWCNT) ou via tiolação (MWCNT-SH). Ademais, também foram funcionalizados MWCNT via amidação com 2 - amino- 2 - hidroximetil - propano - 1,3 - diol (TRIS). Tais nanotubos de carbono (ox-MWCNT, MWCNT-SH e MWCNT-TRIS) foram aplicados na síntese de nanocompósitos com nanopartículas de prata (AgNP) através de reação in situ, na qual os NTCs foram dispersos no meio reacional de obtenção das AgNP por redução dos íons prata por borohidreto de sódio. Após a caracterização físico-química das amostras obtidas, as AgNP assim como seus nanocompósitos com MWCNT-Func (AgNP/ox-MWCNT, AgNP/MWCNT-SH e AgNP/MWCNT-TRIS) foram submetidos à ensaios de atividade antimicrobiana do tipo concentração inibitória mínima (MIC) e ensaios de tempo-morte. Finalmente, as AgNP e seus nanocompósitos foram submetidas à degradação pela ação das folhas de CeP e CeP/ox-MWCNT / Abstract: This doctoracte thesis aims the application of the nanoscience and nanotechnology tools in order to contribute with water/wastewater remediation contamined with traditional pollutants. In this regard, we studied the remediation of metals ions, such as Pb, Cd, Cu, Co, Ni through the filtration of simulated ions effluents with fibrous cerium phophate (CeP) and also its inedit nanocomposites obtained by interaction between CeP and functionalized multi-walled carbon nanotubes (MWCNT-Func). Herein, MWCNT-Func were functionalized by oxidation, thiolation and amidation reactions with 2-amino-2-hydroxymethyl-propane-1,3-diol (TRIS). The MWCNT-Func obtained was named ox-MWCNT, MWCNT-SH and MWCNTTRIS. Adittionally, we prepared silver nanoparticles (AgNP) and their nanocomposites with MWCNT-Func (AgNP/ox-MWCNT, AgNP/MWCNT-SH, AgNP/MWCNT-TRIS) by in situ synthesis method. Moreover, we studied their antibacterial properties. Furthermore, we applied the CeP and CeP/MWCNT-Func nanocomposites as photocalytic materials to remediate water/wastewater simulated effluents wherein AgNP and AgNP/MWCNT-Func were present / Doutorado / Quimica Inorganica / Doutora em Ciências

Orientador: Maria do Carmo Gonçalves / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-24T02:16:34Z (GMT). No. of bitstreams: 1 Andrade_PatriciaFernanda_D.pdf: 6247587 bytes, checksum: f34d80dacc0ecfa31beb35c9a4f8ab70 (MD5) Previous issue date: 2013 / Resumo: Neste trabalho foram preparadas e caracterizadas nanopartículas de prata estabilizadas com polivinilpirrolidona (PVP) e ß-ciclodextrina (ß-CD), que foram incorporadas em matrizes poliméricas, para a obtenção de membranas. As nanopartículas de prata (AgNP) foram sintetizadas pelo método de redução química. Para as AgNP-PVP, foi investigada a influência da concentração do precursor (AgNO3) e da razão molar de PVP em relação ao precursor. A partir dos resultados obtidos, foram selecionadas as melhores condições experimentais para a preparação das AgNP-ß-CD. As AgNP foram caracterizadas por espectroscopias na região do ultravioleta-visível e na região do infravermelho com transformada de Fourier (UV-vis e FTIR), difração de raios X (DRX), espectroscopia de espalhamento de Luz Dinâmico (DLS), microscopia eletrônica de transmissão (TEM) e análise termogravimétrica (TGA). As morfologias das AgNP-PVP e AgNP-ß-CD foram investigadas visando a caracterização da camada de polímero ao redor das nanopartículas, pela técnica de imagem espectroscópica de elétrons associada à microscopia eletrônica de transmissão (ESI-TEM). As nanopartículas estabilizadas com PVP apresentaram diâmetro médio de 45 nm, quando preparadas a partir da concentração de 0,01 mol L-1 e razão molar PVP/AgNO3 igual a 1,5. As nanopartículas estabilizadas por ß-CD apresentaram diâmetro médio de 28 nm, quando preparadas nas mesmas condições indicadas para as de AgNP-PVP. O estudo morfológico da camada polimérica ao redor das AgNP-PVP e AgNP-ß-CD, realizado por ESI-TEM, confirmou a maior concentração de carbono e oxigênio nessa região, sugerindo a existência de uma camada definida e coesa dos estabilizantes envolvendo as nanopartículas. Os valores de concentração mínima inibitória contra a E. coli, após 3 h e 2 h de incubação, foram 12,5 µg mL-1 e 20 µg mL-1 para AgNP-PVP e AgNP-ß-CD, respectivamente. As membranas de polissulfona (PSf) e acetato de celulose (CA), contendo AgNP-PVP e AgNP-ß-CD, respectivamente, foram obtidas pelo método de inversão de fases, tendo como variável a quantidade de AgNP adicionada às matrizes poliméricas. Todas as membranas foram caracterizadas por UV-vis,DRX, FTIR, microscopia eletrônica de varredura com fonte de emissão de campo (FESEM), TEM, calorimetria diferencial de varredura (DSC), TGA, ângulo de contato e fluxo de água. A incorporação de nanopartículas de prata nas membranas de PSf e CA foi realizada utilizando diferentes metodologias, que influenciaram tanto o diâmetro médio das nanopartículas, quanto a morfologia e sua distribuição na matriz polimérica. A incorporação das nanopartículas nas membranas não alterou a estabilidade térmica das matrizes poliméricas, entretanto, aumentou seu caráter hidrofílico e, consequentemente, o fluxo de água. A membrana de PSf, contendo 2% de AgNP, apresentou 100% de inibição de crescimento bacteriano para E. coli, como também a membrana CA para S. aureus e E. coli. As membranas de PSf e CA, contendo 2% de AgNP, apresentaram redução na formação de biofilme para E. coli de 89 ± 1% e 98 ± 3%, respectivamente. Estas membranas podem ser consideradas interessantes em diferentes aplicações, tais como no tratamento de água e recuperação de águas residuais / Abstract: Silver nanoparticles (AgNPs), stabilized with polyvinylpyrrolidone (PVP) and ß-cyclodextrin (ß-CD), were prepared, characterized and incorporated into polymer matrices to produce membranes in this work. The AgNPs were synthesized by the chemical reduction method. The influence of the precursor concentration and PVP molar ratio in relation to the precursor concentration (AgNO3) was investigated for the AgNP-PVP. Based on the results, the best experimental conditions were selected for the preparation of AgNP-ß-CD. The AgNPs were characterized by UV-visible and Fourier transformed infrared spectroscopies (FTIR and UV-vis), X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS) and thermogravimetry analysis (TGA). The morphologies of the AgNP-PVP and AgNP-ß-CD were investigated by electron spectroscopy image associated to TEM (ESI-TEM) to characterize of the polymer layer around the nanoparticles. The nanoparticles which were stabilized with PVP presented an average diameter of 45 nm, when prepared from the 0.01 mol L-1 concentration and 1.5 PVP/ AgNO3 molar ratio. The nanoparticles which were stabilized by ß-CD showed an average diameter of 28 nm, when prepared under the same conditions indicated above. The morphological study of the polymeric layer around the AgNP-PVP and AgNP-ß-CD, carried out by ESI-TEM, confirmed a greater concentration of carbon and oxygen in this region, suggesting the existence of a defined and cohesive stabilizing layer surrounding the nanoparticles. The minimum inhibitory concentration values against E. coli after 2 to 3 hours of incubation were 12.5 µg mL-1 and 20 µg mL-1 for AgNP-PVP and AgNP-ß-CD, respectively. The polysulfone (PSf) and cellulose acetate (CA) membranes, containing AgNP-PVP and AgNP-ß-CD, respectively, were obtained by the phase inversion method, by varying the amount of silver nanoparticles added to the polymer matrix. All the membranes were characterized by UV-vis, XRD, FTIR, field emission scanning electron microscopy (FESEM), TEM, differential scanning calorimetry (DSC), contact angle and water flux. The incorporation of the silver nanoparticles into the PSf and CA membranes was carried out using different methods, which influenced both the average diameter of the nanoparticles and the morphology and their distribution in the polymer matrices. The addition of nanoparticles into the membranes did not change the thermal stability of the polymer matrices, however, it did increase the hydrophilic character and consequently water flux. The PSf membranes containing 2% of silver nanoparticles showed 100% inhibition growth of E. coli, as well as the CA membrane that showed 100% inhibition growth for S. aureus and E. coli. The PSf and CA membranes, containing 2% of silver nanoparticles, presented a reduction in the biofilm formation for E. coli of 89 ± 1% and 98 ± 3%, respectively. These membranes can be considered interesting materials in different applications such as in water treatment and the recovery of residual water / Doutorado / Físico-Química / Doutora em Ciências

Orientadores: Italo Odone Mazali, Fernando Aparecido Sigoli / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-19T18:04:09Z (GMT). No. of bitstreams: 1 Costa_LuizPereirada_D.pdf: 7505198 bytes, checksum: 4a358fa524fc2f2a6b3eadb7a1e9f27a (MD5) Previous issue date: 2011 / Resumo: Neste trabalho foi empregada uma rota de síntese de nanopartículas de prata metálica (NPAg), via redução química de um sal precursor do metal, usando o solvente orgânico N,N-dimetilacetamida (DMA) como agente de redução e estabilização. Foi feito estudo comparativo com a síntese usando o solvente N,N-dimetilformamida (DMF), a fim de relacionar efeito de coordenação das moléculas dos solventes aos íons Ag e o efetivo controle de morfologia, tamanho e grau de dispersão das NPAg formadas. O solvente DMA apresentou maior eficiência no controle do tamanho de NPAg (4-10 nm), cuja morfologia esferoidal não sofreu alteração com o decorrer do tempo (até 24 horas) sob condições ambiente. Na síntese em DMF, o tamanho médio das NPAg obtidas (da ordem de 40-60 nm), indicou menor eficiência de estabilização, observada pela formação de aglomerados de NPAg. Cálculos mecânico-quânticos, a partir da Teoria Funcional de Densidade (DFT) e medidas de voltametria cíclica foram decisivos na proposição de um modelo de cinética de redução dos íons Ag e da influência de algumas propriedades das moléculas orgânicas no efetivo controle de morfologia e tamanho das NPAg obtidas. Foram sintetizadas NPAg suportadas in situ em matrizes hospedeiras de diferentes naturezas: i) suportes mesoporosos e ii) lamelares, a partir de metodologia de síntese simples, em única etapa reacional. Foi possível inferir sobre o papel de matrizes hospedeiras como agentes controladores de morfologia e tamanho das NPAg. Para a matriz mesoporosa de canais ordenados (SBA-15) observou-se a formação de nanobastões e esferas e para as matrizes de estrutura de poros desordenada (PVG® e SMD) observou-se a formação de NPAg esferoidais, variando apenas o tamanho, sugerindo que o crescimento das NPAg está associado ao ambiente em que se encontram confinadas. No estudo inédito da influência das interações interlamelares de matrizes lamelares no controle efetivo da morfologia das NPAg preparadas in situ, observou-se que na matriz lamelar de interação interlamelar mais forte (CTA-Magadiíta) formaram-se nanodiscos de prata, enquanto que para a matriz de interação interlamelar mais fraca (n-but,n-dod-AIPO-Kanemita) formaram-se NPAg esferoidais. A possibilidade de obtenção de nanoestruturas hierarquicamente organizadas, na formação de nanopartículas caroço@casca (NCC) do tipo Ag@SnO2, em reação que combina a redução dos íons Ag e hidrólise e condensação do precursor alcoóxido em única etapa reacional também foi investigada. Técnicas de caracterização como: espectroscopia de absorção na região do UV-Vis e microscopia eletrônica de transmissão foram determinantes na realização deste trabalho, além da difratometria de raios X, espectroscopia vibracional na região do infravermelho e análise elementar, entre outras, que trouxeram informações complementares importantes, conduziram à proposição de afirmativas sobre as sínteses realizadas. Os resultados obtidos permitiram inferir sobre fatores que contribuem para a síntese de NPAg em sistema coloidal, além da síntese de NPAg suportadas em rota experimental simples, bemcom da possibilidade de preparação de NCC Ag@SnO2 / Abstract: This work proposes a new route for the synthesis of metallic silver nanoparticles (NPAg) by chemical reduction of a metal salt precursor (AgNO3), using the organic solvent N,N-dimethylacetamide (DMA) as a reducing and stabilizing agent. A comparative study was performed using the solvent N,N-dimethylformamide (DMF) in order to correlate the coordination of the solvent molecules and metal ions with the shape, size and dispersion of NPAg. The DMA shows greater efficiency in controlling the particle size of NPAg (4-10 nm), whose spheroidal morphology did not change with time. In the synthesis in DMF, the average particle size is in the range of 40-60 nm, due to lower efficiency of surface stabilization during the formation of the NPAg. Quantum-mechanical calculations, based on Density Functional Theory (DFT) and cyclic voltammetry were used to investigate some physico-chemical characteristics of the solvents and their powerfulness as soft base against Ag ions. The results indicate that the DMA is softer than DMF and therefore may coordinate better Ag or Agn species that DMF does. Supported NPAg were synthesized in situ in host matrices of different natures: i) mesoporous supports and ii) layered materials. It was possible to infer about the use of host matrix structure as control agents of the morphology and size of NPAg. For matrix with ordered mesoporous channels (SBA-15) the formation of silver nanorods is observed while spheroidal NPAg is obtained in disordered mesopore structure (PVG® e SMD). Differences in the average particle sizes suggest that the growth of NPAg may be related to the environment in which they are confined. A pioneering study about the influence of the interactions between the layers of lamellar hosts in the effective control of the morphology of in situ prepared NPAg is also presented. Silver nanodisks are obtained into the lamellas of the CTA-Magadiíte that presents strong interlayer interaction, while spheroidal NPAg are formed into the lamellas of the n-but,n-dod-AIPO-Kanemite that has weak chemical forces between the lamellas. The possibility of obtaining hierarchically organized nanostructures, such as the formation of Ag@SnO2 core@shell nanoparticles (NCC), in reaction that combines the reduction of Ag ions and hydrolysis and condensation of the alkoxide precursor in a single step reaction was also investigated. The results allows to infer the factors that contribute to the synthesis of NPAg in colloidal system, and the synthesis of supported NPAg in simple experimental route, as well as the possibility of preparation of Ag@SnO2 NCC / Doutorado / Quimica Inorganica / Doutor em Ciências

Doctor of Philosophy / Department of Chemistry / Christine M. Aikens / Gold and silver particles with dimensions less than a nanometer possess unique characteristics and properties that are different from the properties of the bulk. They demonstrate a non–zero HOMO–LUMO gap that can reach up to 3.0 eV. These differences arise from size quantization effects in the metal core due to the small number of atoms. These nanoparticles have attracted great interest for decades both in fundamental and applied research. Small gold clusters protected by various types of ligands are of interest because ligands allow obtaining gold nanoclusters with given sizes, shapes and properties. Three main families of organic ligands are usually used for stabilization of gold nanoclusters: phosphine ligands, thiolate ligands and DNA. Usually, optical properties of these NPs are studied using optical absorption spectroscopy. Unfortunately, sometimes this type of spectrum is poorly resolved and tends to appear very similar for different complexes. In these cases, circular dichroism (CD) and magnetic circular dichroism (MCD) spectroscopy can be applied. However, the interpretation of experimental CD and MCD spectra is a complicated process. In this thesis, theoretically simulated CD and MCD spectra were combined with optical absorption spectra to study optical activity for octa– and nona– and undecanuclear gold clusters protected by mono– and bidentate phosphine ligands. Additionally, optical properties of bare and DNA protected silver NPs were studied. Theoretical CD spectra were examined to learn more about the origin of chirality in chiral organometallic complexes, and to contribute to the understanding of the difference in chiroptical activity of gold clusters stabilized by different phosphine ligands and DNA–stabilized silver clusters. Furthermore, optical properties of the small centered gold clusters Au₈(PPh₃)₈²⁺ and Au₉(PPh₃)₈³⁺ were examined by optical absorption and MCD spectra using TDDFT. Theoretical MCD spectra were also used to identify the plasmonic behavior of silver nanoparticles. These results showed that CD and MCD spectroscopy yield more detailed information about optical properties and electronic structure of the different chemical systems than optical absorption spectroscopy alone. Theoretical simulation of the CD and MCD spectra together with optical absorption spectra can be used to assist in the understanding of empirically measured CD and MCD and provide useful information about optical properties and electronic structure.

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