A tuberculose é uma doença infecto-contagiosa de proporções continentais. A situação é bastante complexa, pois a doença está diretamente associada às precárias condições sociais, à AIDS e à crescente multirresistência às drogas. Em 1993, a OMS a declarou em estado de emergência, recomendando a DOTS para seu controle. Assim, o presente estudo teve como objetivos identificar: as características pessoais, de condições de vida e de trabalho e de saúde-doença dos pacientes sob DOTS, matriculados em Unidades de Saúde da Família da Supervisão Técnica de Saúde de Vila Prudente/Sapopemba do Município de São Paulo; as potencialidades e os limites da estratégia DOTS sob o ponto de vista desses pacientes e como interpretam a adesão ao tratamento. Após aprovação em Comitê de Ética, foram coletados depoimentos de 11 pacientes de Unidades Básicas de Saúde da Família (UBSF) da Supervisão Técnica de Vila Prudente/ Sapopemba do MSP. O material empírico foi decodificado mediante técnica de análise de discurso e analisado à luz da Teoria da Determinação Social do Processo Saúde-Doença. Os resultados evidenciaram que a tuberculose é uma doença de cunho eminentemente social e ainda impregnada de estigma. Os achados em relação às características pessoais e sobre a manifestação clínica confirmam os dados de literatura. A doença causou mudanças no cotidiano dos sujeitos de estudo, principalmente no que refere ao relacionamento com outras pessoas. A DOTS, em geral, revelou-se como estratégia incorporada ao cotidiano dos sujeitos, e que possibilita o acesso mais facilitado aos serviços de saúde. Os aspectos limitantes da DOTS se devem à distância entre a unidade de saúde e o domicílio, assim como a exposição cotidiana às variações climáticas. A atitude dos profissionais em relação ao paciente contribui para a adesão ao tratamento e para a operacionalização da DOTS / The tuberculosis is a infectum-contagious illness of continental ratios, the third part of the world-wide population is infected and presents risk to develop the disease. The situation is sufficiently complex, therefore the illness directly is associated with the precarious social conditions, the AIDS and the increasing multiresistance to the drugs. In 1993, the OMS declared the tuberculosis in emergency state, recommending the DOTS for the control of the illness. The tuberculosis is a with priority problem of health in Brazil that, together with others 22 developing countries, lodges 80% of the world-wide cases of the illness. The present study it had as objective to identify the meanings, the potentialities and the limits of according to patient strategy DOTS of the local level of the City of São Paulo (MSP). 11 depositions of patients of Basic Units of Health of Família (UBSF) of the Supervision had been collected Technique of Cautious Village Sapopemba of the MSP. The empirical material was decoded by means of technique of analysis of analyzed speech and to the light of the Theory of the Social Determination of the Health-Illness Process. The results had evidenced that the tuberculosis is illness of an eminently social and impregnated matrix of stigma, did not have association of the signals and symptoms to the tuberculosis. The illness caused changes in the form to think or to locate itself ahead of the life, of the process health-illness, in the relationship with others and proper the daily one. The negative aspects to the DOTS if must to the limitation of its operation and the positive aspects to the DOTS confirm that the support strategy, but is not the sufficient for the adhesion. Visa what it makes the vulnerable people to exceed the potentials of increasing in search of the cure is the common things and the projects of life, that stimulate the capacity to surpass the challenges of the life

O estudo teve como principal objetivo analisar a adesão ao tratamento da tuberculose a partir da operacionalização da estratégia Tratamento Diretamente Supervisionado (DOTS), sob a perspectiva de profissionais de saúde que atuavam no controle da doença na região da Supervisão Técnica de Saúde do Butantã - SP. Trata-se de pesquisa qualitativa, baseada nos pressupostos da Teoria da Determinação Social do Processo Saúde-Doença e no conceito de Adesão. No período de maio a julho de 2006, foram entrevistados 22 profissionais de saúde das Unidades Básicas de Saúde (UBS) que desenvolviam a estratégia, incluindo os Coordenadores destas UBS. Foram resguardados os procedimentos éticos. Utilizou-se de técnica de análise de discurso apropriada para o tratamento dos depoimentos, que foram decompostos e analisados a partir das categorias analíticas: significados sobre o processo saúde-doença, a forma como se organiza o trabalho na unidade de saúde, os significados sobre a DOTS e sobre a adesão ao tratamento. Os resultados mostram que, de modo geral, os sujeitos do estudo consideram a tuberculose a partir da perspectiva da multicausalidade, ainda que com ênfase nos aspectos sociais. Identificaram-se atitudes que revelam estigma, decorrentes da falta de conhecimento a respeito da enfermidade e da forma como relacionar-se com o doente. Evidenciaram-se problemas na organização dos serviços, que se referem à trajetória percorrida pelos pacientes para ter acesso ao diagnóstico da tuberculose, além da ausência da busca de sintomáticos respiratórios. Quanto à DOTS, sua estruturação é diversa entre as UBS, no intuito de considerar as necessidades dos doentes no processo terapêutico, mas também devido à falta de conhecimentos dos profissionais, no que diz respeito à operacionalização da estratégia. A equipe de enfermagem é a que mais intensamente participa da DOTS. Para os profissionais de saúde, a estratégia permite manter atenção junto ao doente evitando o abandono do tratamento. Reitera-se, com algumas ressalvas, que a estratégia apresenta impacto na adesão, uma vez que possibilita a criação de vínculo entre o profissional de saúde e o doente. Além disso, verificou-se a necessidade de ampliar o entendimento a respeito do conceito de adesão, dado que não se restringe a um comportamento pessoal e volitivo / The main goal to this research was to analyze the compliance with tuberculosis therapy by use of the DOTS strategy – (Directly Observed Treatment), under the perspective of health professionals’ who carried out the control of tuberculosis in the Supervision of Health region of Butantã in the city of São Paulo, Brazil. This is a qualitative research based on the principles of the Social Determination of the Health-Disease Process Theory and of the concept of compliance. From May to July 2006, 22 Health professionals from the Health Basic Units (HBU), who developed the DOTS strategy, were interviewed, including their unit’s coordinators. Ethical procedures were applied to protect them. By using the appropriate speech analysis technique for the handling the collected material, the interviews were fragmented and analyzed according to analytic categories: understanding about the health-disease process, the way that the work is organized within the Health Unit, the meanings about the DOTS and about the compliance with treatment. The results show that, in general, the subjects of this study consider tuberculosis from the perspective of multicausality, even though with emphasis in the social aspects. Attitudes that reveal stigma were identified, derived from the lack of knowledge about the illness and the way of interacting with the patient. Some problems occurred in the organization of the services that refer to the path taken by the patients to having access to the diagnosis of tuberculosis, as well as the lack of search for respiratory symptomatic. With regards to the DOTS, its structure is diverse among the HBU, in the intention of considering the patients’ needs in the therapeutic process, but also due to the lack of knowledge of the professionals, when it comes to exercising the strategy. The nursing team is the one which participates most intensely in the DOTS. For the health professionals, the strategy allows them to pay close attention to the patient avoiding any dropping out of the treatment. It is certain, with some exceptions, that the strategy has some impact in its initiation, once it allows for a relationship to be created between the health professional and the patient. It was also verified that there is a need to further unfold the understanding of the concept of initiating this strategy, since it isn’t restricted to a personal behavior or to free will

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-08-31T13:00:29Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese Doutorado Johan CD.pdf: 3689018 bytes, checksum: 956c4e0d76742d36ffe10e5bd9f4fa90 (MD5) / Made available in DSpace on 2016-08-31T13:00:29Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese Doutorado Johan CD.pdf: 3689018 bytes, checksum: 956c4e0d76742d36ffe10e5bd9f4fa90 (MD5) Previous issue date: 2016-02-29 / CNPq / No presente trabalho foi investigado o desempenho de nanotubos de TiO2 sensibilizados com quantum dots de CdS na geração de hidrogênio por meio da reação de dissociação da água por meio da fotocatálise e fotoeletrocatálise. Os nanotubos de TiO2 foram obtidos pelo método de anodização (30 V, 1 hora) de chapas de Ti, em etilenoglicol e água contendo íons fluoreto. As amostras anodizadas foram submetidas a tratamento térmico 400°C durante 3 horas. Posteriormente as amostras foram sensibilizadas com quantum dots de CdS via síntese hidrotérmica in situ usando o ácido 3-mercaptopropiônico como agente estabilizante. A eficiência fotocatalítica dos materiais na produção de hidrogênio foi investigada por meio da reação de dissociação da água utilizando como fonte de irradiação um simulador solar. A quantificação do hidrogênio gerado foi determinada por meio de cromatógrafia gasosa. Por outro lado, para estimar a eficiência de geração de hidrogênio via fotoeletrocatálise, as amostras foram avaliadas como fotoânodos e medidas da fotocorrente gerada pela irradiação em uma célula fotoeletroquímica (PEC) de três eletrodos foram realizadas. A sensibilização dos nanotubos de TiO2 com os quantum dots de CdS a partir da síntese hidrotérmica in situ, permitiu uma boa impregnação e distribuição uniforme dos quantum dots ao redor da superfície dos nanotubos, de acordo com as análises de EDS e XPS. O perfil de profundidade de XPS mostrou que a concentração de CdS permaneceu praticamente inalterada (homogênea) ao longo da matriz nanotubular. A presença de ânions sulfato evidenciou a oxidação do material preferentemente na superfície. Os nanotubos conferem uma proteção ao CdS frente à oxidação e protegem também os quantum dots quanto à fotocorrosão na solução de sacrifício S2-/SO32- utilizada. Este comportamento define uma boa estabilidade na fotocorrente gerada como mostrado em experimentos de longa duração (20 horas) sob irradiação. Os resultados experimentais mostraram três comportamentos diferentes para a geração de H2 quando o tempo de síntese dos QDs de CdS aumenta. Foram observados, efeitos similares, antagônicos e sinérgicos frente à atividade fotocatalítica em relação aos nanotubos de TiO2. O efeito antagônico parece estar relacionado com a presença de duas populações de tamanhos de QDs de CdS, onde a população com um band gap menor atua como uma armadilha para os elétrons fotogerados pela população com um band gap maior, diminuindo a atividade fotocatalítica do TiO2 na região ultravioleta. A transferência de elétrons a partir dos QDs de CdS para o TiO2 foi comprovada pelos resultados de UPS combinados com as medidas do band gap óptico. A maior absorção no visível após a sensibilização com o CdS combinada com a transferência de elétrons possibilita um incremento na taxa de geração de hidrogênio por meio da fotocatálise a partir de luz visível de quase zero para os nanotubos de TiO2 até cerca de 0,3 μmol cm-2 h-1 após sensibilização com os QDs de CdS. No caso da fotoeletrocatálise em uma PEC, a taxa de geração de H2 a partir de luz visível estimada pela fotocorrente gerada após a sensibilização (1,79 μmol cm-2 h-1) chega a ser até 12 vezes maior que para os nanotubos de TiO2 sem sensibilizar (0,15 μmol cm-2 h-1). / In the present work, we investigated the performance of TiO2 nanotubes sensitized with CdS quantum dots on the photocatalytic and photoelectrocatalytic H2 production reaction. TiO2 nanotubes were obtained by anodization of Ti foil, followed by annealing to crystallize the nanotubes into anatase phase. Afterwards, the samples were sensitized with CdS quantum dots via an in situ hydrothermal route using 3-mercaptopropionic acid as the capping agent. This sensitization technique permits high loading and uniform distribution of CdS quantum dots onto TiO2 nanotubes. The XPS depth profile showed that CdS concentration remains almost unchanged (homogenous), while the concentration relative to the sulfate anion decreases by more than 80 % with respect to the initial value after ~200 nm in depth. The presence of sulfate anions is due to the oxidation of sulfide and occurs in greater proportion in the material surface. This protection for air oxidation inside the nanotubular matrix also protected the CdS from photocorrosion in sacrificial solution leading to good stability properties proved by a long duration photocurrent measurements. The effect of the sizes of CdS quantum dots attached to TiO2 nanotubes on the hydrogen production via photocatalysis was investigated. The experimental results showed three different behaviors when the CdS size is increased in the sensitized samples, e.g., similar, deactivation and activation effects on the hydrogen production with regard to TiO2 nanotubes. The deactivation effect was related with two populations of sizes of CdS, where the population with a shorter band gap acts as a trap for the electrons photogenerated by the population with a larger band gap. Electron transfer from CdS quantum dots to TiO2 semiconductor nanotubes was proven by the results of UPS combined with optical band gap measurements. This property facilitates an improvement of the visible-light photocatalytic hydrogen evolution rate from zero, for TiO2 nanotubes, to approximately 0.3 μmolcm-2h-1 for TiO2 nanotubes sensitized with CdS quantum dots. The hydrogen generation rate estimated from photocurrents measurements via photoelectrocatalysis in PEC systems was also investigated. The hydrogen generation rate after sensitization was improved from 0,15 μmol cm-2 h-1 to 1,79 μmol cm-2 h-1, near to 12 times better performance under visible-light irradiation.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-02-13T14:42:08Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) dissertação para imprimir.pdf: 1944013 bytes, checksum: 446b8ae7597e9bfcfe53826edaa4a028 (MD5) / Made available in DSpace on 2017-02-13T14:42:08Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) dissertação para imprimir.pdf: 1944013 bytes, checksum: 446b8ae7597e9bfcfe53826edaa4a028 (MD5) Previous issue date: 2014-08-20 / FACEPE / Neste trabalho foram sintetizados quantum dots de CdTe e CdTe:Gd3+ tendo o ácido mercapto succínico como estabilizante, visando uma potencial aplicação como agente de contraste bimodal para imagem ótica e magnética. A difração de raios-X evidenciou a formação dos QDs. Após quantificação dos íons dopantes por Espectrometria de Emissão Ótica com Plasma Indutivo Acoplado (ICP-OES), verificou-se 75,7% dos íons Gd3+ adicionados ficaram na nanopartícula. A grande quantidade de íons aderidos à nanopartícula, além da observação do aumento da relaxividade com a diminuição do pH e o deslocamento do estiramento das carbonilas por espectroscopia de infravermelho, são fatores que indicam que os íons Gd3+ aderiram aos QDs pela coordenação com o estabilizante e não por dopagem. A presença do íon gadolínio não alterou o deslocamento do máximo de absorção dos QDs e possivelmente interferiu na cinética de estabilização das superfícies, pois houve a diminuição da intensidade da luminescência dos mesmos. / In this work were synthesized quantum dots of CdTe and CdTe:Gd3+ having mercapto succinic acid (MSA) as a stabilizer, looking forward their use as a bimodal contrast agent for optical and magnetic images. The X-ray diffraction showed the formation of QDs. The quantification of dopants by Optical Emission Spectrometry with Inductive Coupled (ICPOES) Plasma, showed that 75.7% of Gd3+ ions were added in the nanoparticle. The large amount of ions bonded to the nanoparticle and the observation of increased relaxivity with decreasing pH and the observed shift of the stretching of carbonyls by infrared spectroscopy, are factors that indicated that Gd3+ ions were adhered to the QDs by coordinating with the stabilizer and not by doping. The presence of gadolinium ions did not change the absorption maximum band of the QDs, but probably changed the stabilization kinetics at the QD surface, due to the observed luminescence intensity decreasing.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-03-28T13:13:15Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Cabral Filho, PE Tese - PPGCB.pdf: 40667296 bytes, checksum: 0fe805957d5ab95d53bed853da61deb5 (MD5) / Made available in DSpace on 2017-03-28T13:13:15Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Cabral Filho, PE Tese - PPGCB.pdf: 40667296 bytes, checksum: 0fe805957d5ab95d53bed853da61deb5 (MD5) Previous issue date: 2016-07-15 / CAPES / Os pontos quânticos ou quantum dots (QDs) são nanocristais fluorescentes de semicondutores com propriedades ópticas únicas, tendo como principais vantagens: (1) alta resistência à fotodegradação, possibilitando o acompanhamento de eventos biológicos em tempo real e, (2) superfície ativa, permitindo a conjugação a biomoléculas que vão propiciar especificidade às marcações, além de possibilitar também sua ligação a outras nanopartículas. Com isso, é possível quantificar uma variedade de biomoléculas em células e tecidos e desenvolver nanossondas bimodais (magnético-fluorescentes) baseadas em QDs. O desenvolvimento de nanopartículas bimodais pode aliar as vantagens das técnicas baseadas em fluorescência com as de imagem por ressonância magnética (IRM). Entretanto, a obtenção de sondas bimodais é ainda um desafio, pois durante a conjugação devem ser mantidas as propriedades fluorescentes e magnéticas das nanopartículas, e com isso ainda há poucos trabalhos que façam aplicações em sistemas biológicos. O objetivo desta tese se caracteriza pelo desenvolvimento de sondas com propriedades multimodais baseadas em QDs de Telureto de Cádmio (CdTe) associadas a nanopartículas magnéticas de óxido de ferro como marcadores sítio-específicos em células cancerígenas. Inicialmente os QDs foram conjugados covalentemente à transferrina (Tf) [QDs-Tf] para a quantificação específica de seus receptores (TfRs) em células HeLa e em duas linhagens de glioblastoma (U87 e DBTRG). Através de ensaios de saturação do TfR, foi possível inferir sobre a taxa de renovação deste receptor nessas células. Os resultados mostraram que as células HeLa e as DBTRG possuem uma maior quantidade do TfR quando comparadas às U87. As DBTRG apresentaram maior taxa de renovação do TfR, quando comparadas aos outros dois tipos, demonstrando que os conjugados QDs-Tf são potenciais ferramentas para o estudo da biologia celular do câncer. Posteriormente, nanossondas bimodais (QDsMNPs), baseadas em QDs associados a nanopartículas magnéticas de óxido de ferro, foram obtidas por conjugação covalente. De acordo com as caracterizações, QDs-MNPs mantiveram suas propriedades ópticas e magnéticas e apresentaram-se como potenciais sondas inespecíficas para fluorescência e para aquisição de imagens por RM ponderadas em T2 (tempo de relaxação nuclear transversal). A conjugação prévia dos QDs a Tf, além de fornecer informações sobre a biologia do câncer, auxiliou também na padronização da marcação específica do TfR em células cancerígenas e no estabelecimento de protocolos de conjugação das sondas bimodais a Tf. Por fim, as QDs-MNPs foram conjugadas covalentemente a Tf e essa nova sonda multimodal [(QDs-MNPs)-Tf] reconheceu especificamente os TfR em células HeLa. As caracterizações indicaram que o sistema multimodal não apresentou alteração significativa nas propriedades ópticas e exibiu uma maior relaxividade transversal (r2), se mostrando igualmente potencial sonda para análise por fluorescência e IRM ponderada em T2. Neste trabalho foram obtidas nanossondas promissoras para serem aplicadas na compreensão da biologia celular do câncer, além de auxiliar em métodos diagnósticos e terapêuticos para essa doença. / Quantum dots (QDs) are fluorescent semiconductor nanocrystals with unique optical properties, which have as major advantages: (1) the high resistance to photobleaching, making possible to monitor biological events in real-time and, (2) active surface, allowing the conjugation not only with biomolecules for specific labeling, but also to other nanoparticles. Thus, it would be possible to quantify a variety of biomolecules in cells and tissues, as well as to develop bimodal nanoprobes (fluorescent-magnetic) [BNPs] based on QDs. The development of BNPs can help to combine the advantages of the fluorescence with the resonance magnetic imaging techniques. However, the preparation of bimodal probes can still be considered a challenge, since the fluorescent and magnetic nanoparticles’ properties need to be preserved after conjugation. Therefore, there are still few works applying BNPs in biological studies. The aim of this thesis was to develop nanoprobes, with multimodal properties, based on cadmium telluride (CdTe) QDs conjugated with iron oxide magnetic nanoparticles (MNPs), for site-specific labeling in cancer cells. For this, initially, QDs were covalently coupling to transferrin (Tf) [QDs-Tf] and used to quantify the transferrin receptor (TfRs) in HeLa cells as well as in two glioblastoma lines (U87 and DBTRG). Furthermore, by a TfR saturation assay, it was possible to study the recycling rate of this receptor in cells studied. The results showed that HeLa and DBTRG cells present a higher amount of TfRs when compared to U87. DBTGR showed a higher TfR recycling rate, when compared to the other two lineages, demonstrating that QDs-Tf conjugates are potential tools to study the cancer cell biology. BNPs, based on the conjugation of QDs with MNPs (QDs-MNPs), were obtained by covalent coupling. According to characterizations, the BNPs remained with their optical and magnetic properties preserved and showed to be potential unspecific probes for fluorescence analysis and for T2-weighted magnetic resonance imaging (MRI) acquisition. The conjugation of QDs to Tf, performed previously, was a valuable step not only to provide us information about the biology of cancer cells, but also for the standardization of TfR specific labeling and the establishment of protocol to conjugate the BNPs with Tf. Therefore, QDs-MNPs were also covalently coupling to Tf and this new multimodal nanotool [(QDs-MNPs)Tf] was also able to recognize specifically TfRs in HeLa cells. The multimodal nanosystems presented their fluorescent properties practically unchanged and also exhibited a higher transversal relaxivity (r2), when compared to bare BNPs, showing likewise potential to be used for fluorescence and T2-weighted MRI analyses. In this work, it was developed promising nanoprobes, able to be applied for the cancer cell biology comprehension, and with potential for helping in the improvement of diagnostic and therapeutic methods for this disease.

Les propriétés des quantum dots (QDs) en font des sondes adaptées à la reconnaissance moléculaire. Leur pic d’émission en fluorescence est très étroit et ajustable, tandis que la section efficace de leur spectre d’absorption est très large. En outre, ils sont très brillants et résistent mieux au photoblanchiment que les colorants organiques conventionnels.Notre objectif a été de concevoir un nouveau type de sondes fluorescentes pour une détection rapide à l’échelle de la molécule unique. L’utilisation d’agrégats contenant plusieurs milliers de QDs, plutôt que celle de QDs individuels, permet d’accroître le signal de fluorescence et de simplifier les modalités de détection. La morphologie et la chimie de surface des premiers agrégats préparés n’ont pas pu être contrôlées en les recouvrant avec des molécules de surfactants courts ou une couche de polymère en solution aqueuse. La stratégie centrale de ce manuscrit a permis d’assembler les QDs en nanobilles (NBs) monodisperses de quelques centaines de nanomètres de diamètre, encapsulées dans une couche de silice Stöber. Leur stabilité colloïdale et leur photostabilité ont ainsi été conservées. Un nouveau type d’hybride polymère-silane a été greffé sur la silice. Il présente des chaînes zwittérioniques, garantissant la solubilité en milieu aqueux et une adsorption non spécifique minimale, ainsi que des fonctions réactives pour la bioconjugaison. La réactivité de NBs fonctionnalisées par de la streptavidine avec des billes commerciales biotinylées a été démontrée. Nos résultats préliminaires ont également montré que les NBs peuvent être intégrées dans un dispositif microfluidique pour être comptées individuellement. / Using nanotechnology for molecular diagnostics holds many advantages e.g. an improvement in the simplicity and the sensitivity of analysis. Semi-conductor nanocrystals or quantum dots (QDs) demonstrate several unique properties that make them suitable probes for biomolecular recognition. These QDs present narrow size-tunable emission spectra and a broad excitation spectrum; in addition, they offer higher photostability and brightness than conventional organic dyes. Our aim was to design a new diagnostic probe based on fluorescent nanobeads containing QDs, envi-sioned as a tool for fast and single-molecule detection. An even brighter fluorescence and easily detectable analytical signals could indeed be achieved by aggregating several thousand of QDs together, as compared to single QDs. Coating QD clusters with small surfactants or a polymer layer didn’t provide morphological control or a suitable surface chemistry for bioconjugation. The strategy that we developed consists in self-assembling QDs into monodisperse nanobeads of a few hundreds of nanometers in diameter, on top of which a silica shell was grown by a Stöber-inspired process. This allowed us to protect their colloidal and photo-stability. A new type of multidentate polymer-silane hybrid was subsequently grafted onto the silica shell, presenting a zwitterionic chain for water solubility and antifouling, as well as reactive functions for conjugation with biomolecules. We succeeded in reacting streptavidin-conjugated nanobeads with commercial biotinylated beads. Preliminary results have also shown that we can integrate the nanobeads into a microfluidic system for an efficient single-particle counting.

Les nitrures d’éléments III sont des matériaux clés du fait de leurs excellentes propriétésoptoélectroniques. Ces semi-conducteurs possèdent trois polymorphes de structure et desbandes interdites allant de l’ultraviolet (GaN, AlN) à l’infrarouge (InN).Dans un premier temps, ces travaux se concentrent sur l’élaboration en continu denitrure de gallium (GaN) à partir d’un précurseur unique : le tris(diméthylamido) gallaneemployé dans un solvant anhydre (nitrurant ou non-nitrurant) en conditions supercritiquesdans un réacteur microfluidique. Les particules obtenues présentent des tailles nanométriques(~3 nm) et une structure cristalline complexe. Des luminescences intenses dans l’UV, décaléesvers de plus hautes énergies comparées aux matériaux massifs sont mesurées pour cesmatériaux, en accord avec des phénomènes de confinement quantique. L’absence d’émissiondans le visible permet de démontrer la quasi-absence de défauts dans les nitrures élaborés.Dans un second temps, l’étude porte ensuite sur la préparation de la solution solide InxGa1-xN(0 ≤ x ≤ 1). L’approche choisie est différente : la mise en contact d’une source d’azote et d’unesource métallique est ici privilégiée. Le travail de chimie exploratoire effectué sur les différentstypes de précurseurs envisagés met en avant l’intérêt des cupferronates combinés avec leHMDS pour l’élaboration de nanoparticules d’(InGa)N. Un mélange intime et une répartitionhomogène des deux atomes métalliques sont démontrés pour toutes les compositions et sontconfirmés par l’étude des propriétés optiques. Un décalage de l’énergie maximale d’émissionavec l’augmentation du taux d’indium (jusqu’à 40 %) en adéquation avec les valeurs attenduesest mesuré, permettant d’enregistrer des signaux de l’UV jusqu’au rouge. / LII-nitrides are key materials thanks to their excellent optoelectronic properties. Thesesemiconductors have three structural polymorphs and a wide range of bandgaps can beaccessed varying the composition from ultraviolet (GaN, AlN) to infrared (InN).First, this study focuses on the synthesis of gallium nitride from a single source precursor– the tris(dimethylamido) gallane – employed in an anhydrous solvent in supercriticalconditions in a microfluidic reactor. The as-prepared particles present nanometric size (~3 nm)and have a complex crystalline structure. High intensities UV photoluminescence, shiftedtowards higher energies compared to bulk GaN, are recorded for these materials, in agreementwith quantum confinement effect. The lack of visible emission demonstrate the preparation ofdefect-free material. Then, the focus is brought to the preparation of the solid solution InxGa1-xN (0 ≤ x≤ 1) with a different approach. The reaction of a metal source with a nitrogen sourceis studied. Reactions between metal cupferronates and HMDS are deeply investigated after abrief exploratory chemistry work. An intimate mixing of both metals with a homogeneousdistribution is demonstrated for the entire solid solution and is validated with the opticalproperties. A continuous decrease of the energy maximum with increasing indium content (upto 40 % in indium) is in agreement with the theoretical values, yielding to luminescence fromUV to red.

Les carbon dots (CDs), dernier membre de la famille des nanoparticules (NPs) carbonées à avoir été découverts, sont des particules hydrophiles quasi-sphériques qui sont généralement présentées comme biocompatibles et seulement faiblement toxiques. Ils sont facilement accessibles par voie de synthèse et peuvent être tout aussi aisément modifiés par modification chimique des groupes fonctionnels présents à leur surface. Leurs propriétés de fluorescence intrinsèques les rendent intéressants pour de nombreuses applications, notamment dans le domaine biomédical où les CDs trouvent des applications en tant que vecteurs de principes actifs, comme d’autres NPs développées dans ce domaine. Les travaux développés au cours de cette thèse visaient premièrement à identifier les propriétés physicochimiques intrinsèques des CDs qui conditionnent leur toxicité. Pour cela, le profil toxicologique d’une large collection de CDs présentant des propriétés de taille, charge et chimie de surface a été établi en utilisant des modèles in vitro et in vivo. Nous avons pu montrer ainsi que, bien que la taille des NPs joue un rôle important dans leur toxicité, elle ne constitue pas à elle seule un facteur prédictif de cette dernière. En effet, la charge et la chimie de surface régissent de façon importante les interactions entre les NPs et l’environnement biologique dans lequel elles sont introduites et, donc, leur toxicité. Le deuxième objectif de cette thèse était d’étudier le potentiel qu’offrent les CDs dans le domaine de la délivrance de gènes. Nous avons pu montrer la supériorité de CDs préparés à partir d’acide citrique et de bPEI600 sur tous les autres CDs cationiques préparés et évalués dans notre étude. Une approche systématique nous a permis d’améliorer, pas à pas, l’efficacité des CDs jusqu’à surpasser celle du bPEI25k, un agent de référence dans le domaine.Dans l’ensemble, nos études ont ouvert de nouvelles perspectives dans le domaine des NPs en apportant des éléments de compréhension des mécanismes de leur toxicité et en identifiant des conditions de production qui permettent d’optimiser leur propriétés en tant qu’agent de transfection. / Carbon dots (CDs) are the latest member of the family of carbon nanoparticles (NPs) to be discovered. They were isolated for the first time in 2004, during electrophoresis purification of carbon nanotubes. In addition to their nanometric size, these objects are almost spherical and hydrophilic, and are generally presented as biocompatible and very weakly toxic NPs. They are fairly easily accessible by synthesis and can be conveniently modified by reaction of the functional groups present on their surface (amines, carboxylic acids, alcohols, etc.). Finally, they exhibit intrinsic fluorescence properties, are relatively resistant to photobleaching, and can be excited by multi-photon irradiation. Thus, like the other members of the family of carbon NPs (graphene, nanodiamonds, fullerenes, nanotubes), CDs have remarkable properties which are the subject of intense research for applications in fields as different as those of electronics, catalysis, energy storage, imaging, and medicine. In the latter area, CDs can find applications as drug delivery systems, like other NPs successfully developed in this field. The work developed during this thesis had two distinct objectives. The first one was to identify the intrinsic physicochemical properties responsible for the toxicity of NPs. For this, the toxicological profile of a large collection of CDs produced in the laboratory and exhibiting various size, charge, and surface chemistry was characterized using in vitro lung models and mice. We found that although the size of the NPs plays an important role it is not, by itself, a predictive element of the toxicity of the NPs. The charge and the surface chemistry largely effect the interactions between the NPs and the biological medium systems and, therefore, their intrinsic toxicity. The second objective of this thesis was to assess the potential of CDs in the field of drug delivery as synthetic gene carriers. We were able to show the superiority of NPs prepared from citric acid and bPEI600 over all other cationic CDs produced in the laboratory. A systematic evaluation has allowed us, step by step, to improve the efficiency of these transfection agents, to exceed that of bPEI25k, a gold standard for in vitro transfection, without significant toxicity. Overall, this work opens up new horizons in NPs research that may provide 1-a better understanding of the toxicological mechanisms of NPs, especially their determinants, and 2-identification of the relationship between the CDs synthesis methods and the efficiency of these NPs as DNA transfection reagents.

Quantum dots exhibit strongly size-dependent optical and electrical properties. The ability to join the dots into complex assemblies creates many opportunities for scientific discovery. This motivated our present research work on QDIPs, DWELLs, and graphene like QDs. The intention of this research was to study the size dependent achievements of QDIPs, DWELLs, and graphene like QDs with those of competitive technologies, with the emphasis on the material properties, device structure, and their impact on the device performance. In this dissertation four research studies pertaining to optical properties of quantum dot and dot-in-a-well infrared photodetectors, I-V characteristics of graphene quantum dots, and energy and spin texture of germanene quantum dots are presented. Improving self-assembled QD is a key issue in the increasing the absorption and improving the performance. In the present research work, an ideal self-assembled QD structure is analyzed theoretically with twenty-hole levels (Intraband optical transitions within the valence band) and twenty-electron energy levels (DWELL). Continuing the efforts to study self-assembled QDs we extended our work to graphene like quantum dots (graphene and germanene) to study the electronic transport properties. We study numerically the intraband optical transitions within the valence band of InxGa1-xAs/GaAs pyramidal quantum dots. We analyze the possibility of tuning of corresponding absorption spectra by varying the size and composition of the dots. Both ‘x ’ and the size of the quantum dot base are varied. We have found that the absorption spectra of such quantum dots are more sensitive to the in-plane incident light. We present numerically obtained absorption optical spectra of n-doped InAs/In0.15Ga0.85As/GaAs quantum dot-in-a-well systems. The absorption spectra are mainly determined by the size of the quantum dot and have weak dependence on the thickness of the quantum well and position of the dot in a well. The dot-in-a-well system is sensitive to both in-plane and out-of-plane polarizations of the incident light with much stronger absorption intensities for the in-plane-polarized light. We also present theoretically obtained I-V characteristics of graphene quantum dots, which are realized as a small piece of monolayer graphene. We describe graphene within the nearest-neighbor tight-binding model. The current versus the bias voltage has typical step-like shape, which is due to discrete energy spectrum of the quantum dot. The current through the dot system also depends on the position of the electrodes relative to the quantum dot. In relation to graphene quantum dots, we present our study of buckled graphene-like materials, like germanene and silicene. We consider theoretically germanene quantum dot, consisting of 13, 27, and 35 germanium atoms. Due to strong spin-orbit interaction and buckled structure of the germanene layer, the direction of the spin of an electron in the quantum dot depends on both the electron energy and external perpendicular electric field. With variation of energy, the direction of spin changes by approximately 4.50. Application of external electric field results in rotation of electron spin by approximately 0.50, where the direction of rotation depends on the electron energy.

Experimental investigations of the optical properties of InGaN/GaN quantum dots are presented. A pulsed laser is used to perform time-integrated and time-resolved microphotoluminescence, photoluminescence excitation, and polarisation-resolved spectroscopy of single InGaN quantum dots under a non-linear excitation regime. The first micro-photoluminescence results from InGaN/GaN quantum dots grown on a non-polar crystal plane (11^-<sub style='position: relative;left: -.4em;'>2</sub>0) are presented. Time-resolved studies reveal an order of magnitude increase in the oscillator strength of the exciton transition when compared to InGaN quantum dots grown on the polar (0001) plane, suggesting a significantly reduced internal electric field in non-polar InGaN quantum dots. Polarisation resolved spectroscopy of non-polar InGaN quantum dots reveals 100% linearly polarised emission for many quantum dots. For quantum dot emissions with a polarisation degree less than unity, a fine structure splitting between two orthogonal polarisation axes can be resolved in an optical setup with a simple top-down excitation geometry. A statistical investigation into the origins of spectral diffusion in polar InGaN quantum dots is presented, and spectral diffusion is attributed to charge carriers trapped at threading dislocations, and itinerant and trapped carriers in the underlying quantum well layer which forms during the growth procedure. Incorporating quantum dots into the intrinsic region of a p-i-n diode structure and applying a reverse bias is suggested as a method to reduce spectral diffusion. Coherent control of the excited state exciton in a non-polar InGaN quantum dot is experimentally demonstrated by observation of Rabi rotation between the excited state exciton and the crystal ground state. The exciton ground state photoluminescence is used as an indirect measurement of the excited state population.