Neste trabalho são apresentados estudos do efeito de interfaces nas propriedades fotofísicas e fotoquímicas do azul de metileno (AM) e de derivados fenotiazínicos com o intuito de avaliar o potencial destes compostos como fotossensibilizadores (FS) em terapia fotodinâmica. As propriedades físico-químicas do AM foram estudadas em soluções de SOS e observou-se que a presença do AM em solução altera o equilíbrio entre as micelas de SOS, diminuindo o valor da concentração micelar crítica de 7mmolL-1 para 70µmoIL-1. A presença das micelas em solução também interfere nas propriedades do AM. Em baixas concentrações de SOS há formação de dímeros de AM, constatados pelo aumento da absorbância em 580nm e diminuição da emissão de fluorescência. A caracterização das espécies transientes mostrou a existência de moléculas de azul de metileno no estado triplete (3AM) e de oxigênio singlete em soluções com altas concentrações de SOS e a formação de espécies radicalares do AM em baixas concentrações do tensoativo. Esta observação sugere que o mecanismo fotoquímico do AM é dependente da sua concentração local próxima de interfaces carregadas. As interações do AM e de alguns de seus derivados fenotiazínicos (tionina, azure A e azure B) com vesículas e com células HeLa foram estudadas e em ambos os casos observou-se que as moléculas com estruturas assimétricas são incorporadas em maior extensão. Em estudos de fototoxicidade, os compostos assimétricos apresentaram maior nível de morte celular do que o verificado para os compostos simétricos. Entretanto, ao se considerar a incorporação em células, os compostos simétricos se mostraram mais eficientes por molécula. Foi desenvolvido um método para determinação do 10gP dos fotossensibilizadores (FS) por voltametria com microeletrodos que se mostrou reprodutível. Novos FSs assimétricos derivados do Azure A com duas caudas hidrofóbicas de 4, 6 e 8 carbonos (AzC4, AzC6 e AzC8) foram sintetizados. Esses novos compostos possuem eficiências de fluorescência semelhantes ao AM. O composto AzC4 apresenta eficiência de geração de oxigênio singlete bem próxima à do AM (0,56), enquanto os outros dois compostos têm uma eficiência de geração de oxigênio singlete cerca de duas vezes menor. Este comportamento se deve ao fato dos FSs com cadeias carbônicas maiores interagirem mais fortemente entre si, apresentando maior grau de agregação. Os compostos sintetizados apresentam maior incorporação em vesículas que os compostos anteriormente estudados, indicando que a assimetria da molécula favorece a incorporação, assim como, o comprimento da cadeia hidrofóbica. Resultados de incorporação em células HeLa, mostraram que o composto AzC4 interage mais facilmente com a membrana celulare apresenta maior nível de morte celular devido à sua maior incorporação. / The effect of interfaces on photophysical and photochemical properties of methylene blue (MB) and its derivatives was studied in this work, aiming to emploit their potencial as photosensitizers (PS) in photodynamic therapy.The presence of MB in SDS solutions affect the micelle equilibrium decreasing the apparent critical micelle concentration of SDS from 7mmolL-1 to 70µmoIL-1. The properties of MB were also affected. At low SDS concentrations the formation of MB dimers was detected by the increase in the absorption in 580 nm and decrease of fluorescence emission. The characterization of transient species of MB showed the existence of MB molecules in the triplet state and emission of singlete oxygen at large SDS concentration and the formation of MB radicals in small surfactant concentration. These observations suggest that the photochemical mechanism of MB depends on its local concentration close to charged interfaces.The interactions of MB as well as other phenotiazine derivatives with synthetic vesicles and HeLa cells were studied. In both cases, the PS with asymmetrical structure presented higher degrees of incorporation. Studies of phototoxicity showed that the PS with asymmetrical structures present higher degree of cell death than the symmetrical compounds. However, if one consider the degree of incorporation the symmetrical compounds are more efficient per molecule. A method to determinate logP by voltammetry with microelectrodes was developed, showing good repeatability. New asymmetric photosensitizers derived from Azure A with two hydrophobic chains of 4, 6 or 8 carbons (AZC4, AZC6 e AzC8) were synthesized in order to study structure/activity relationship. These new compounds presented similar fluorescence efficiency to MB. The oxygen singlet generation efficiency of AZC4 is similar to MB, while the efficiency of the other PSs was twice smaller. This behavior was explained in terms PS aggregation, due to their longer hydrophobic chains. The synthesized PSs presented larger degree of incorporation than the commercial PSs, showing the role of asymmetry and hydrophobicity in incorporation yields. Incorporation in HeLa cells showed that AZC4 interacts more strongly with cells than the other synthesized PSs due to the rigidity of plasmatic membrane. Under the same illumination conditions, AzC4 was the PS that presented higher degree of cell death as a result of its larger incorporation in cells.

Submitted by Nadir Basilio (nadirsb@uninove.br) on 2016-06-01T19:47:46Z No. of bitstreams: 1 Maria Eugenia Simoes Onofre De Santi.pdf: 2254123 bytes, checksum: b5a3993a9c227dee841fbc6c8cca349d (MD5) / Made available in DSpace on 2016-06-01T19:47:46Z (GMT). No. of bitstreams: 1 Maria Eugenia Simoes Onofre De Santi.pdf: 2254123 bytes, checksum: b5a3993a9c227dee841fbc6c8cca349d (MD5) Previous issue date: 2014-12-04 / Vulvovaginal candidiasis is the second most common cause of vaginal infection and it affects 75% of all women at least once during their lifetime. Recurrent vulvovaginal candidiasis represents a challenge to gynecological practice, since some patients frequently experience re-occurrences shortly after antifungal treatment. Antimicrobial photodynamic therapy (PDT) is considered a therapeutically approach in treating fungal infections. The aim of this study was to investigate the efficiency of PDT against yeast infection in animal model. We tested two photosensitizers, methylene blue and PpNetNI combined to light sources. Microbial analysis was performed following treatment and seven days later, and histological examination of vaginal tissue was performed after PDT treatment. PDT inactivated yeast cells and it reduced in 1 log10 for both photosensitizers used and these low-fungal counts were maintained follow 7 days. Histological analysis showed an inhibition of neutrophil influx process in PDT groups and no side effects on tissue was observed. In conclusion, two PDT managements produced antimicrobial effects in this mice infection model and PDT can be considered as potential therapeutic approach to decrease fungal counts in vaginal infection. / Candidíase vulvovaginal é a segunda mais comum infecção ginecológica e afeta 75% das mulheres pelo menos uma vez durante seu período reprodutivo. A candidíase vulvovaginal recorrente representa um desafio à prática ginecológica, uma vez que muitas pacientes experimentam recorrências imediatamente após finalizarem um tratamento. A terapia fotodinâmica (PDT) é considerada uma abordagem terapêutica no tratamento de infecções fúngicas. O objetivo deste estudo foi investigar a eficácia da PDT em vulvovaginite causada por Candida albicans em modelo animal. Testamos dois fotossensibilizadores: Azul de metileno e uma protoporfirina: PpNetNI, combinados com fontes de luz adequadas. A análise microbiológica foi realizada imediatamente e sete dias após o tratamento e a análise histológica do canal vaginal foi realizada até quatro horas após o tratamento. A contagem fúngica foi reduzida em 1 log10 após a aplicação da PDT para os dois fotossensibilizadores testados e se manteve após sete dias. A análise histológica demonstrou uma redução no influxo neutrofílico nos grupos tratados e nenhum efeito colateral deste tratamento foi observado. Em conclusão, o tratamento com os dois fotossensibilizadores produziu efeitos antimicrobianos no modelo animal e a PDT pode ser considerada uma abordagem terapêutica para diminuir a infecção fúngica no canal vaginal.

The diploma thesis is focused on surfactants as compounds of fire fighting foams. Fire fighting foams have several characteristics including foaming, aquatic toxicity and biodegradability, which cause the environmental impact. This diploma thesis deals with the contamination of the soil by the large amount of the extinguishing water. The experimental part of the diploma thesis describes the determination of surfactants by the mobile analysis and the measurement of the methylene blue index.

This master's thesis is focused on study of transport processes in hydrogels based on humic acids. For this purpose is used methods unsteady diffusion in cuvettes, which was studied the transport of organic dyes, specifically methylene blue and rhodamine 6G, in agarose hydrogel without the addition and with the addition of individual standards humic acids (Leonardite, Elliott Soil, Suwannee River II and Pahokee Peat). This method is based on spectrophotometric monitoring of concentration changes of dyes depending on space of the cuvette and on time. The aim of this thesis was to investigate the effects of interactions between diffusing dye and the particular type of gel to the resultant effective diffusion coefficient of dye. The experiments indicate that the presence of humic acid in the hydrogel greatly affects the transport of selected dyes.

Orientador: Rogério Pinto Mota / Resumo: Polímeros a plasma são uma classe de materiais que possuem aplicações em diversos tipos de indústrias, como biomédica, alimentícia, embalagens, eletrônica, farmaceutica, entre outras. Esses materiais possuem características que os diferem dos polímeros convencionais, como uma estrutura química ordenada aleatoriamente, boa adesão a diferentes substratos e possuem cadeias muito entrelaçadas. Estes polímeros podem ser utilizados para a função de drug delivery, podem ser carregados com um medicamento e liberá-lo quando in vivo, este conceito de drug delivery permite a realização de um tratamento localizado e com uma dose mais segura de medicamento. O processo de polimerização a plasma também tem características que o difere da polimerização convencional, ele é capaz de realizar reações que demandam muita energia e não poderiam acontecer por química convencional, os parâmetros aplicados podem ser ajustados para customizar até certo ponto o material obtido e não gera resíduos. Inicialmente a polimerização a plasma era realizada em baixa pressão, mais recentemente a alternativa de realizar o processo em pressão atmosférica vêm ganhando destaque por ser relativamente mais barata e pelas características diferentes da descarga e dos polímeros a plasma resultantes. Existem muitas configurações de fontes de plasma em pressão atmosférico, dentre elas os jatos de plasma (APPJs), nestas fontes o plasma é gerado por descargas DBD ou corona no interior de tubos ou cavidades e é expelida para ... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

M. Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology. / Organic water pollutants such as dyes are difficult to biodegrade. In this study Fenton, photo-Fenton and photocatalysis were used to degrade methylene blue dye in the presence of copper oxide catalysts. The copper oxide catalysts were prepared with a precipitation reduction method. The effect of different preparation parameters on the catalyst properties and catalytic activity were investigated. The reducing agents, ascorbic acid (ASC, C6H8O6), hydrazine (N2H4), sodium boron hydride (NaBH4) and glucose (C₆H₁₂O₆) could be used to obtain the desired Cu2O phase. ASC, N2H4 and NaBH4 were able to reduce copper (II) to copper (I) at room temperature whereas glucose required a higher reduction temperature. Stoichiometric amounts of the reducing agents ASC, N2H4 and glucose and double the stoichiometric amount of NaBH4 were required to obtain Cu2O. A further increase in the amounts of NaBH4 and N2H4 resulted in the formation of copper metal (Cu (0)). High amounts of ASC did not over-reduce the copper. ASC also functioned as capping molecule and anti-oxidant preventing the oxidation of the Cu2O to CuO in air after preparation. Hydrazine was thus not able to protect the Cu2O against oxidation. The SEM results showed that an increase in the amount of the precipitating agent, NaOH, resulted in an increase in the particle sizes. The particle shapes changed from spherical to cubic when a high amount of NaOH was used with hydrazine as reducing agent. Smaller particle sizes were obtained when CuCl2 was used instead of CuSO4 and Cu(NO3)2. Larger crystallites formed when the preparation temperature was increased from room temperature to 100°C with glucose as reducing agent. TEM and XRD analyses showed that the micro-particles seen in SEM analyses are made up of nano-particles. The catalysts were not active for photocatalysis which may be explained by the oxidation of these nano-particles to form the photocatalytic inactive CuO. The catalysts were shown to be active for Fenton and photo-Fenton degradation. The addition of graphene and activated carbon to the Cu2O catalysts were detrimental to the catalytic activity. The percentage degradation of methylene blue by the Fenton reaction increased with an increase in the BET surface area from 1.5 m2/g to 10 m2/g and a further increase in the surface area resulted in a decrease in the percentage degradation. A direct correlation between the Fenton catalytic activity and the pore size were found which indicate that the reaction was mass transfer limited.

The photocatalytic degradation of the wastewater dye pollutant methylene blue (MB) at ZnO nanostructured porous thin films, deposited by direct current reactive magnetron sputtering on Si substrates, was studied. It was observed that over 4 photocatalytic cycles (0.3 mg · l−1 MB solution, 540 minUV irradiation), the rate constant k of MB degradation decreased by ∼50%, varying in the range (1.54 ÷ 0.78) · 10–9 (mol·l−1·min−1). For a deeper analysis of the photodegradation mechanism, detailed information on the nanostructured ZnO surface morphology and local surface and subsurface chemistry (nonstoichiometry) were obtained by using scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (XPS) as complementary analytical methods. The SEM studies revealed that at the surface of the nanostructured ZnO thin films a coral reef structure containing polycrystalline coral dendrites is present, and that, after the photocatalytic experiments, the sizes of individual crystallites increased, varying in the range 43 ÷ 76 nm for the longer axis, and in the range 28 ÷ 58 nm for the shorter axis. In turn, the XPS studies showed a slight non-stoichiometry, mainly defined by the relative [O]/[Zn] concentration of ca. 1.4, whereas [C]/[Zn] was ca. 1.2, both before and after the photocatalytic experiments. This phenomenon was directly related to the presence of superficial ZnO lattice oxygen atoms that can participate in the oxidation of the adsorbed MB molecules, as well as to the presence of surface hydroxyl groups acting as hole-acceptors to produce OH· radicals, which can be responsible for the generation of superoxide ions. In addition, after experiments, the XPS measurements revealed the presence of carboxyl and carbonyl functional groups, ascribable to the oxidation by-products formed during the photodegradation of MB.

Les ARN 5'-triphosphates (TP) et 5'-coiffés sont des molécules très convoitées des biologistes pour des études structurales par cristallographie ou comme outils thérapeutiques. Actuellement, ces oligonucléotides sont produits dans de faibles quantités via des procédés enzymatiques dépendants de la nature du nucléoside situé à l'extrémité 5'. Ces travaux se sont donc inscrits dans l'enjeu majeur de mettre au point une méthode chimique sur support solide qui permette l'accès à ces ARN 5'-fonctionnalisés en quantités importantes et sans restriction de séquences.Ce manuscrit rapporte une nouvelle méthode efficace de synthèse sur support solide d'ARN 5'-TP à grande échelle indépendante du nucléotide situé à l'extrémité 5' ou de la longueur de la séquence ARN. De plus, cette stratégie a été étendue avec quelques modifications à la synthèse d'analogues enzymatiquement plus stables de type: ARN 5'-β,γ-méthylène-TP, -(α-P-thio)-TP et -(α-P-thio)-(β,γ-méthylène)-TP.Une deuxième partie présente la synthèse supportée et l'évaluation antivirale de courts adénylates 2-5A 5'-TP portant des groupements enzymolabiles de type acétalesters en position 3' du ribose. Une dernière partie est consacrée à l'élaboration de nouvelles stratégies pour la synthèse d'ARN 5-coiffés. La première approche est un procédé en deux étapes où la structure coiffe (Gppp) est ajoutée sur support solide suivie d'une N7- méthylation enzymatique en solution, alors que la seconde est une méthode plus directe entièrement chimique. Par ailleurs, le couplage chimique de la coiffe sur les ARN supportés nécessite l'emploi d'un acide de Lewis. Ainsi l'utilisation de chlorures métalliques « verts » produits à partir de métaux de transition extraits de la biomasse a été évaluée dans la réaction du couplage de la coiffe sur les ARN. / 5'-triphosphates RNAand 5'-capped RNA are high valuable molecules which serve as important substrates for structural and mechanistic studies or drugs. To date, these oligonucléotides are produced by enzymatic process in low yields with a weak variability of the 5'-end. To overcome this bottleneck we aimed to develop a chemical access on solid-support of these 5'-functionalized RNA in great amount without any limitations in the RNA sequence.Here, a robust, reproducible, and scalable method for the solid-phase synthesis of 5′-triphosphate RNA is presented. Furthermore, this strategy was extended to produce enzymatic resistant analogs of the triphosphate counterpart like: 5'-β,γ-methylene-TP, -(α-P-thio)-TP et -(α-P-thio)-(β,γ-methylene)-TP RNA.In a second part, the solid-phase synthesis of short adenylates 2-5A 5'-TP bearing biolabile acetalester groups on nucleosides 3'-hydroxyls and their antiviral activities are described.Finally, we focused on developing two approaches for the production of 5'-capped RNA. One is a two-steps process which consists in the coupling of the cap structure on solid-support followed by an enzymatic N7-methylation in solution while the other one is a straightforward chemical strategy. Beside, the chemical coupling of the cap moiety on solid-supported RNA requires the use of Lewis acids. Then, the ability of « green » metal chlorides prepared from phytoextracted heavy metals to promote this reaction was studied.

La thèse est divisée en trois chapitres indépendants. Chimie du β-lactames : Synthèse d'α-éthylène et d'α-alkylidène-β-lactames en utilisant la réaction de Kinugasa. Chimie de l'acylsilane : application d'une réaction aldolique intramoléculaire asymétrique sur un dérivé d'acylsilane nouvellement synthétisé. - Chimie médicinale: synthèse de nouvelles molécules à but anticancéreux.Dans le premier chapitre la réaction de Kinugasa a été appliquée pour la première fois à des alcynes vrais, portant en position propargylique un groupe partant permettait d'accéder directement et en une étape aux méthylène- et alkylidene β-lactames recherchés. Dans le second chapitre, la synthèse de molécules originales possédant à la fois une fonction acylsilane et un aldéhyde en position éloignée, et l'aldolisation intramoléculaire asymétrique a été explorée. Dans le dernier chapitre, notre objectif était de restaurer les propriétés apoptotiques au sein des cellules cancéreuses afin d'obtenir de nouveaux composés à activité antitumorale. A partir de données obtenues par modélisation moléculaire, nous avons fait le design de plusieurs séries d'analogues d'un inhibiteur connu(MIM-1) de la protéine anti-apoptotique Mcl-1. Huit composés ont été synthétisés et testés pour trois types de cellules cancéreuses (sein, ovaire et le mélanome). / The thesis is divided into three chapters:- β-lactams chemistry: synthesis of α-methylene and α-alkylidene-β-lactams using the Kinugasa reaction.- Acylsilane chemistry : applying asymmetric intramolecular aldol reaction on a newly synthesized acylsilane derivatives. - Medicinal chemistry: synthesis of new molecules with anticancer aimes. In the first chapter, Kinugasa reaction was applied for the first time with an alkyne bearing a nucleofuge in propargylic position that allowed us to discover a way of synthesis of exoalkylidene β-lactams. In the second chapter, a new acylislane derivatives bearing an aldehyde functional group in a remote position of the molecule were prepared, and asymmetric intramolecular aldolization reaction was performed. In the last chapter, our goal was to reinduce the pro-apoptotic properties in cancer cells in order to obtain new antitumor compounds. Starting from data obtained through molecular modeling studies, we designed and prepared several series of analogs for a known inhibitor (MIM-1) of the anti-apoptotic protein Mcl-1. Eight compounds have been synthetized and screened towards three types of cancer cells (breast, ovarian and melanoma).

This work describes the application of a variety of Lewis bases, encompassing predominantly N-heterocyclic carbenes (NHCs), but also the use of imidazoles, aminopyridines, amidines and isothioureas, as effective catalysts in the dearomatisation of heterocyclic carbonates, predominantly the rearrangement of oxazolyl carbonates to their C-carboxyazlactone isomers by means of the Steglich rearrangement. This rearrangement reaction has been investigated extensively, with the development of simplified reaction procedures and the invention of domino cascade protocols incorporating this transformation. In an attempt to understand the mechanism of this O- to C-carboxylation process, a number of interesting observations have been made. Firstly, the class of NHC has an important factor in promoting the rearrangement, with triazolinylidenes being the most effective. Secondly, an interesting chemoselectivity has been delineated using triazolium-derived NHCs, prepared using weak bases (typically Et₃N) or strong metallated bases; both alkyl and aryl oxazolyl carbonates undergo smooth rearrangement with triazolinylidenes derived from strong metallated bases such as KHMDS, while only aryl oxazolyl carbonates undergo rearrangement using Et₃N. Extensive effort has focused towards the development of asymmetric variants of these protocols, primarily towards the design, synthesis and evaluation of chiral NHC precatalysts. To this end, a number of chiral azolium salts have been prepared, encompassing a number of different NHC classes, including C₁- and C₂-imidazolinium salts, C₂-imidazolium salts and a range of triazolium salts. Efforts towards the asymmetric catalysis of the Steglich rearrangement of oxazolyl carbonate substrates have given an optimal 66% ee. Similar rearrangements have been demonstrated with the related furanyl heterocyclic substrate class, producing a mixture of α- and γ-carboxybutenolides. In contrast to the analogous oxazolyl carbonates, the regioselectivity of this rearrangement is dependent upon the nature of the Lewis base employed. Amidines and aminopyridines give a mixture of the α- and γ- regioisomers with generally the α-regioisomer being preferred, while a triazolium-derived NHC gives rise to predominantly the thermodynamically more stable γ-carboxybutenolide. Using amidines or aminopyridines, this rearrangement has been shown to proceed via an irreversible C-C bond-forming process, but in contrast, the rearrangement using the NHC proceeds via an equilibrium process with an optimised regioselectivity of >98:2 for the γ-carboxybutenolide regioisomer over the α-regioisomer. Whilst the asymmetric variant using chiral NHCs has proven unfruitful, rearrangements using a chiral isothiourea have given high levels of regioselectivity towards the α- regioisomer and with excellent levels of enantiodiscrimination (77–95% ee).