No description available.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2018-05-03T14:10:04Z No. of bitstreams: 1 pedrovictoralmeidapessanha.pdf: 2319111 bytes, checksum: 6718ea3032cf8200f1974eed7e9ba421 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-09-03T15:57:11Z (GMT) No. of bitstreams: 1 pedrovictoralmeidapessanha.pdf: 2319111 bytes, checksum: 6718ea3032cf8200f1974eed7e9ba421 (MD5) / Made available in DSpace on 2018-09-03T15:57:11Z (GMT). No. of bitstreams: 1 pedrovictoralmeidapessanha.pdf: 2319111 bytes, checksum: 6718ea3032cf8200f1974eed7e9ba421 (MD5) Previous issue date: 2018-02-26 / O PEDOT:PSS (poli(3,4-etilenodioxitiofeno):poli(estirenossulfonato)) é um polímero condutor da classe dos politiofenos amplamente utilizado como camada aceitadora de lacunas na confecção de dispositivos fotovoltaicos. Neste trabalho estudou-se via espectroscopia Raman ressonante, SERS e de absorção UV-VIS-NIR as propriedades ópticas do PEDOT:PSS puro e na presença de AuNPs. O PEDOT:PSS foi sintetizado por polimerização oxidativa com persulfato de sódio e da mistura de persulfato com sulfato férrico hidratado, seguida de purificação com resina de troca iônica ou diálise em água deionizada. A evolução das sínteses foi monitorada através de espectroscopia UV-VIS-NIR, pela qual evidenciou-se a existência de dois regimes eletrônicos distintos para o processo de síntese do PEDOT:PSS, com uma cinética de reação mais rápida para as sínteses realizadas com a mistura de sais. Os polímeros formados apresentam elevado grau de oxidação, caracterizado pela forte absorção de radiação eletromagnética pelas espécies que contém pólarons em torno de 800 nm e bipólarons em cerca de 950 nm. Verificou-se a eficiência dos métodos de purificação por agitação com resina de troca iônica e diálise em água deionizada. A purificação por diálise mostrou-se distinta da obtida por agitação com resinas de troca iônica, rendendo polímeros menos dopados que aqueles purificados com resinas, o que foi atribuído à reorganização das cadeias do polímero mediante a migração via difusão simples e pressão osmótica de íons pequenos e das menores cadeias de PSS para a solução de alimentação. A evolução do perfil vibracional foi monitorada através da espectroscopia Raman ressonante com comprimento de excitação de 633, 785 e 1064 nm. A variação para região de maior número de onda das bandas atribuídas ao grupo tiofeno, responsável pela alta deslocalização de carga das espécies condutoras, indicou que os polímeros formados possuem alto grau de oxidação, com a existência de dois regimes para a evolução do perfil vibracional. A dopagem que ocorre durante o processo de síntese favorece a formação das espécies mais oxidadas na matriz polimérica, e o processo de purificação do PEDOT:PSS altera a estrutura do polímero. Filmes finos e opacos foram obtidos, e apresentaram resistência de folha comparável àquela obtida com polímeros disponíveis comercialmente. Observou-se ainda, através da espectroscopia SERS de cadeias pequenas de PEDOT:PSS adsorvidas sobre nanopartículas de ouro, com radiação incidente de 1064 e 785 nm, a intensificação de modos vibracionais característicos das espécies oxidadas, mais próximos da superfície metálica, embora não exista evidência de interação específica entre o polímero e as nanoestruturas. / PEDOT: PSS is a conductive polymer of the polythiophene class widely used as the hole injection layer in photovoltaic devices. In this work, resonance Raman, SERS and UVVIS-NIR spectroscopies were used to study the optical properties of pure PEDOT: PSS and modified with AuNPs. PEDOT: PSS was synthesized via oxidative polymerization with sodium persulfate and with persulfate mixture with ferric sulfate hydrate, followed by purification with ion exchange resin or dialysis in deionized water. The evolution of the syntheses was monitored via UV-VIS-NIR spectroscopy, in which the existence of two distinct electronic regimes for the synthesis process was evidenced, with a faster kinetics for the syntheses performed with the mixture of salts. The polymers formed exhibited a high level of oxidation, characterized by a strong absorption of electromagnetic radiation by the species that contain polarons and bipolarons. The efficiency of purification methods with ion exchange resin compared to dialysis in deionized water was also evaluated. Purification by dialysis proved to be distinct from stirring with ion exchange resins, yielding less doped polymers than those purified with resins, which was attributed to the rearrangement of the polymer chains by migration of small ions and the small PSS chains for the feed solution. The evolution of the vibrational profile was monitored by resonant Raman spectroscopy with excitation wavelength of 633, 785 and 1064 nm. The variation for the region of high wavenumber of the bands attributed to the thiophene group, responsible for the high delocalization of charge in the conducting species, indicated that the polymers formed have a high degree of oxidation, with the existence of two regimes for the evolution of the vibrational profile. Doping that occurs during the synthesis process favored the formation of more oxidized species in the polymeric matrix, and the purification process of PEDOT: PSS changed the structure of the polymer. Thin and opaque films were obtained, and showed sheet resistance comparable to that obtained with commercially available polymers. It was also observed, through SERS spectroscopy of small chains of PEDOT:PSS adsorbed on gold nanoparticles, using incident radiation of 1064 and 785 nm, the intensification of vibrational modes characteristic of the oxidized species, probably near the metallic surface, although there was no evidence of specific interaction between the polymer and the nanostructures.

SERRS spektra of biological materials are very komplex, because they consist of signals from all molecules present in cells. In this text are presented SERRS spektra of antitumor drugs and its komplex with DNA. Experimental are rated on doxorubicin and another antitumor druha and on study of theirs potential by treatment for tumors. Doxorubicin belong to clase antracycline antibiotics and is used for stop of tumor cells reproduction. Scientists found still new ways, new drugs. SERRS is one of possibilities for study of this drugs and theirs interaction with DNA.

Cette thèse a premièrement permis le développement d’une méthode de détection non-enzymatique de l’ADN. Les techniques enzymatiques couramment utilisées, comme la Polymerase Chain Reaction (PCR), échouent souvent dans l’analyse d’échantillons anciens ou transformés. L’ADN subit en effet de nombreuses dégradations post mortem, parmi lesquelles certaines bloquent les enzymes ADN-polymérases. Notre méthode combine hybridation et détection par SERRS (Surface Enhanced Resonant Raman Scattering), permettant la détection et la quantification de séquences d’ADN dégradées réfractaires à l’analyse par PCR. De nouvelles perspectives s’ouvrent donc en paléogénétique. Cette thèse aborde également le rôle des surfaces minérales dans l’origine des acides nucléiques. Les surfaces minérales pourraient avoir piégé et concentré les briques élémentaires de ces biopolymères, contribuant ainsi à leur construction. Les travaux existants se sont concentrés sur des minéraux comme la montmorillonite, qui n’était cependant pas abondante à l’Hadéen/Archéeen. La minéralogie de la Terre primitive aurait plutôt été dominée par les phyllosilicates ferromagnésiens. Nous avons étudié l’adsorption de nucléotides sur des minéraux plus cohérents avec le contexte géologique, en variant les paramètres environnementaux. Ce travail permet de préciser le mécanisme d’adsorption des nucléotides sur les surfaces minérales, ainsi que les conditions de l’origine du matériel génétique. / The first goal of this thesis was the development of a non-enzymatic DNA detection method. Current enzymatic techniques such as Polymerase Chain Reaction (PCR) often fail in analyzing ancient or processed samples. Indeed DNA undergoes numerous post-mortem degradations, among which some are known to block the bypass of DNA-polymerases. Our method combines hybridization and SERRS (Surface Enhanced Resonant Raman Scattering) spectroscopy, and allows the detection and quantification of degraded DNA sequences that are refractory to PCR analysis. This novel detection method therefore opens new perspectives, especially in paleogenetics. This thesis also aims at studying the role of mineral surfaces in the origin of nucleic acids. Mineral surfaces might have trapped and concentrated the elementary bricks of those biopolymers, thus contributing in their formation. Previous work has focused on minerals such as montmorillonite, although it might not have been abundant during the Hadean/Archean. The primitive Earth’s mineralogy would have been preferentially dominated by Fe-Mg rich phyllosilicates. We have therefore studied the adsorption of nucleotides on minerals we think are relevant to the geological context, and have varied the environmental conditions. This work allows characterizing the adsorption mechanism of nucleotides on mineral surfaces, as well as environmental conditions of the origin of genetic material.

Récemment, la famille des dichalcogénures de métaux de transition (TMDs) (MoS2, WS2, MoSe2...) a suscité l'intérêt de nombreuses équipes de recherche en raison de leurs propriétés optiques, électroniques et spintroniques exceptionnelles. Ma thèse est centrée sur l'association de monocouches de TMDs à des nano-structures plasmoniques. Ces dernières apportent une exaltation des propriétés d'absorption, de diffusion et d'émission optiques qui peuvent être mises à profit dans divers domaines d'applications tels que l'opto-électronique, la photo-catalyse ou les capteurs. Dans une première partie je me suis intéressée à l'interaction plasmon-exciton dans des systèmes hybrides constitués de couches de MoSe2 élaborés par dépôt chimique en phase vapeur (CVD) et transférées sur les nanodisques d'or. La résonance plasmon est contrôlée par le diamètre et la séparation entre les nano-disques. Grâce à des mesures de transmission optique et de photoluminescence, et à une analyse détaillée des réponses spectrales basée sur un modèle analytique et des simulations numériques, j'ai mis en évidence un couplage de type Fano entre les plasmons de surface des nanodisques et les transitions excitoniques de MoSe2. J'ai étudié la dépendance de ce couplage en fonction de la taille des disques, du nombre de monocouches de MoSe2 déposées et aussi en fonction de la température. Une analyse quantitative des résultats a été menée en simulant numériquement non seulement le champ local plasmonique mais aussi son couplage avec le moment dipolaire des transitions excitoniques. Pour compléter l'exploration des propriétés optiques du système MoSe2@Au, je me suis intéressée à la diffusion Raman dans des conditions d'excitation résonante et non-résonante de la transition hybride plasmon-exciton. L'idée principale étant que la résonance plasmonique apporte une exaltation de la diffusion Raman par effet SERS (Surface Enhanced Raman Scattering) tandis que les transitions excitoniques contribuent par l'effet Raman résonnant. Cette combinaison des résonances plasmonique et excitonique conduit à un effet SERS résonant. J'ai ainsi pu distinguer les contributions relatives de ces deux résonances, notamment grâce à l'imagerie confocale de la diffusion Raman. J'ai également montré que, dans ces conditions d'excitation résonnante de la transition plasmon-exciton, un phénomène d'hyperthermie a lieu. la modélisation par simulation numérique du champ proche optique et de la diffusion Raman a été utile pour comprendre les principaux facteurs limitatifs de l'exaltation Raman. Ensuite, la couche de MoSe2 a été utilisée comme substrat de nanoparticules d'Au. Les mesures de photoluminescence ont révélé une extinction quasi-totale de l'émission de la photoluminescence. Afin d'expliquer ce phénomène, deux possibilités ont été discutés : (i) le passage de la structure de bande électronique de la couche de TMD d'un semiconducteur à gap direct à indirect à cause de la contrainte imposée par les nanoparticules d'Au (ii) le désordre structural dû au dépôt des nanoparticules d'Au (iii) le transfert des porteurs photo- générés du semiconducteur vers le métal. Grâce aux mesures Raman, et à l'émission radiative des nanoparticules d'Au, j'ai mis en évidence un phénomène de transfert de charges entre le semi conducteur et le métal. Pour compléter les interprétations proposées, j'ai mené une étude comparative avec les propriétés optiques de couche de TMD couvertes \nolinebreak de silice. Ce travail de thèse a été mené au sein du groupe NeO du CEMES et dans le cadre d'une collaboration avec le groupe du Professeur Jun Lou de l'université de Rice à Houston. / Transition metal dichalcogenide materials (TMDs) are increasingly gaining attention, due to their unique optical, spintronic, and electronic properties. These properties result from the ultimate confinement in 2D monolayers of a direct band-gap semiconductor and the lack of inversion symmetry in the crystallographic structure. To control and enhance the optical response of these materials, it is interesting to integrate them with plasmonic nano-resonators. The TMDs/plasmonic hybrid systems have been extensively studied for plasmon-enhanced optical signals, photocatalysis, photodetectors, and solar cells. In this context, this thesis deals with the interaction between TMD monolayers and gold nanostructures. In a first part, an hybrid system composed of CVD grown MoSe2 monolayers transferred on gold nanodisks was studied. Surface plasmon resonance was tuned by controlling the nanodisks size and the inter-disks separation. The optical properties of the nanostructures are probed by means of spatially resolved optical transmission and photoluminescence spectroscopies. Fano-type coupling regime between the surface plasmon of the gold nanodisks and the MoSe2 exciton was evidenced by a quantitative analysis of the optical extinction spectra based on an analytical model. Our interpretations were supported by numerical simulations. The number of MoSe2 monolayer dependence as well as the Temperature dependence of the plasmon-exciton interaction was investigated. Our results were quantatively analysed on the nanometric scale by studying the local electromagnetic near-field and the excitonic transition dipole momentum interaction. Furthermore, the Raman scattering of MoSe2@Au system was carried out. A particular situation was investigated where a resonant interaction between the surface plasmon of nanodisks and A exciton of v occur. The contribution of these two resonances leads to a resonant surface enhanced Raman scattering (SERRS) effect. The Raman Scattering excitation is selected to resonantly excite the Surface Plasmon resonance and MoSe2 excitonic transition simultaneously. The relative contribution of the surface Plasmon and the confined exciton to the resonant Raman scattering signal is pointed out. In this resonant condition, a hyperthermia effect was detected. Numerical simulations of the SERS gain were useful to figure out the main factors affecting the SERS intensity enhancement in MoSe2@Au. In a second part, the TMD monolayer was used as a substrate of Au nanoparticles. Au nanoislands were deposited on mono- and few-layered MoSe2 flakes. Photoluminescence (PL) measurements revealed a net quenching of the MoSe2 photoluminescence. To figure out the origin of this quenching three possibilities were discussed (i) the charge transfer between the TMD monolayer and the Au particles (ii) the direct to indirect gap transition of the TMD electronic band structure caused by the strain induced by the metal deposition (iii) structural disorder imparted by the nanoparticles in the TMD/metal interface. Owing to the Raman scattering measurements and using the radiative emission of the gold nanoparticles, we evidenced a charge transfetrt between the metallic nanostructures and the semiconductor. In order to complement our interpretations a comparative study with respect to optical properties of TMD covered by a silica film was carried out. The present work was held within the NeO group in CEMES, in a frame of a collaboration with the group of thr Pr. Jun Lou from Rice university, Houston.

AABBSSTTRRAACCTT Dimers and small aggregates as well as compact aggregates of Ag nanoparticles (NPs) were assembled and chemically anchored to supporting surfaces. The supporting surfaces were either glass slides or SiO2 - coated Cu or Au grids for TEM, both chemically functionalized by 3-aminopropyltrimethoxysilane (APTMS). Compact aggregates of Ag NPs incorporating protoporphyrin IX (PPIX) molecules were prepared by adsorption of chlorides in the presence of PPIX. Dimers and small aggregates of Ag NPs were assembled by selected molecular linkers: 4,4'-diaminoazobenzene (DAAB), 4,4'-diaminoterphenyl (DATP) and 5,10,15,20-tetrakis(4-aminophenyl)porphine (TAPP). The most efficient strategy of dimers and small aggregates preparation has been their assembling by a three - step procedure involving (i) attachment of isolated Ag NPs to the NH2 groups of APTMS functionalized TEM grid, (ii) attachment of molecular linker (with two functional NH2 groups in para position) to Ag NPs by a one terminal NH2 group, and (iii) attachment of Ag NPs to the second, free terminal NH2 group of the linker. In this procedure, the control over the perpendicular orientation of the bifunctional linker and its attachment by one terminal group to Ag NP surface has been accomplished by functionalization of Ag NPs by adsorbed citrate...

Cette thèse a premièrement permis le développement d'une méthode de détection non-enzymatique de l'ADN. Les techniques enzymatiques couramment utilisées, comme la Polymerase Chain Reaction (PCR), échouent souvent dans l'analyse d'échantillons anciens ou transformés. L'ADN subit en effet de nombreuses dégradations post mortem, parmi lesquelles certaines bloquent les enzymes ADN-polymérases. Notre méthode combine hybridation et détection par SERRS (Surface Enhanced Resonant Raman Scattering), permettant la détection et la quantification de séquences d'ADN dégradées réfractaires à l'analyse par PCR. De nouvelles perspectives s'ouvrent donc en paléogénétique. Cette thèse aborde également le rôle des surfaces minérales dans l'origine des acides nucléiques. Les surfaces minérales pourraient avoir piégé et concentré les briques élémentaires de ces biopolymères, contribuant ainsi à leur construction. Les travaux existants se sont concentrés sur des minéraux comme la montmorillonite, qui n'était cependant pas abondante à l'Hadéen/Archéeen. La minéralogie de la Terre primitive aurait plutôt été dominée par les phyllosilicates ferromagnésiens. Nous avons étudié l'adsorption de nucléotides sur des minéraux plus cohérents avec le contexte géologique, en variant les paramètres environnementaux. Ce travail permet de préciser le mécanisme d'adsorption des nucléotides sur les surfaces minérales, ainsi que les conditions de l'origine du matériel génétique.

Metabolomics is a post genomic field of research concerned with the study of low molecular weight compounds within a biological system permitting the investigation of the metabolite differences between natural and perturbed systems (such as cells, organs and tissues). Rapid identification and discrimination of biological samples based upon metabolic differences and physiological status in microbiology, mammalian systems (particularly for disease diagnosis), plants and food science is highly desirable. Volatile organic compound (VOC) profiling is a novel area of research where the composition of the VOCs emitted by the biological samples can be correlated to its origin and physiological status. The aim of this project was to investigate the applicability of VOC profiling as a potential complementary tool within metabolomics.In this project the discrimination of bacteria using a novel gas phase separation method was investigated and the development of VOC-based profiling tools for the collections of VOCs emitted from biological samples was also studied. The optimisation and validation of a high throughput method for VOC analysis was achieved and this was used to assess wound healing.VOC metabolite profiling was further extended to the discrimination of S. typhimurium contaminated meat; the study was conducted in parallel with metabolite profiling analysis for the analysis of non-volatile small molecules. Finally, enhanced vibrational spectroscopic techniques were applied to the characterisation and screening of dye molecules in contaminated foodstuffs using Raman spectroscopy. This thesis clearly demonstrates that VOC metabolic profiling is a complementary tool within the metabolomics toolbox, one of its great attractions is that it permits the characterisation of biological samples in a rapid and non-invasive manner. The technique provides detailed chemical information regarding the VOC composition present above the headspace of the sample and can be used to understand its physiological status and biological origin. VOCs metabolite profiling will become a valuable tool for non-invasive analysis of many biological systems. Raman spectroscopy is a sensitive and non-destructive technique which can generate detailed chemical and structural information regarding the analyte under investigation with little or no sample preparation needed. The effect of the weak Raman signal can be significantly amplified by coupling the analyte molecule to surfaces of nanoparticles and demonstrated that it is ideal for analysing aqueous dye solutions in a quantitative manner.

Two types of 3-dimensional (3D) Ag nanosponge aggregates were prepared and tested as samples for surface-enhanced Raman scattering (SERS) and as active surfaces for surface- enhanced luminescence. 3D Ag nanosponge aggregates were assembled from 2D fused fractal aggregates (D = 1.87 ± 0.02) prepared by modification of Ag nanoparticle (NP) hydrosol resulting from the reduction of AgNO3 by NH2OH·HCl. For SERS measurements, 3D Ag nanosponge aggregates with incorporated [Ru(bpy)3]2+ cations and chloride anions were prepared and overlayed by a thin layer of aqueous phase. For SEL measurements, the 3D Ag nanosponge aggregates were assembled from fused fractal aggregates of chloride- modified Ag NPs. After preparation the active surface was overlayed by a 1×10-5 M aqueous solution of [Ru(bpy)3]2+ . The SERRS (1×10-15 M) and SER(R)S (1×10-14 M) limits of detection of [Ru(bpy)3]2+ determined at 445 and 532 nm excitations, respectively, correspond to the single molecule level of the complex detection. Its achievement is attributed to a large electromagnetic mechanism enhancement experienced by [Ru(bpy)3]2+ incorporated in "hot spots", an efficient localization of "hot spots" in the 3D aggregate to the focus of the laser beam in micro-Raman spectral measurements and to a molecular resonance contribution to the...

In this diploma thesis, SERRS(Surface - enhanced resonance Raman Scattering) and SERS (Surface - enhanced Raman Scattering), surface of plasmon extinction spectra and TEM images of systems with tetracationic zinc porphyrin ZnTMPyP and silver nanoparticles (Ag NPs) were studied and interpreted. The systems with isolated nanoparticles and the systems with compact aggregates were investigated. The systems with isolated nanoparticles were prepared by addition of ZnTMPyP to hydrosol of Ag NPs. NaCl was added to this system and so compact aggregates were prepared. SERRS and SERS spectra of ZnTMPyP were studied at excitation wavelengths λexc= 441.6 nm a 532 nm. Firstly, stationary systems and secondly dynamic development of hydrosol Ag NPs → Ag NPs/ ZnTMPyP → Ag NPs/ ZnTMPyP/ NaCl systems for 680 s was investigated. Time evolution of SERRS and SERS spectra were analyzed by factor analysis (FA) and time evolution of spectra extinction plasmon were measured. FA showed a strong increase of the signal of ZnTMPyP after the addition of NaCl, i.e. after conversion of isolated nanoparticles to compact aggregates. In these systems with high concentration of ZnTMPyP the increase of signal was succeeded by its decreased. With help of FA the limit of SERRS spectral detection (λexc= 441,6 nm) and limit of SERS spectral...