This thesis studies the different ways in which the localized plasmon heating effect of gold nanostructures -activated by plasmon excitation via visible and/or NIR irradiation- can be used to obtain different outcomes following the nanofabrication of applicable devices. Both spatial and temporal control were obtained for each one of the systems developed upon the incorporation of plasmonic gold nanostructures. Spatial control was enabled in hybrid mesoporous drug delivery systems fabricated in this thesis through the localized surface plasmon heating effect that allowed the modification of the dynamics of diffusion of the cargo being delivered, thus giving rise to different rates of release that can be controlled by plasmon excitation. At the same time, the plasmon heating effect proved to be capable of controlling the start of the release by dismantling thermo-responsive gates previously incorporated, thus enabling also a wavelength-controlled feature that enhances the versatility of these systems. Spatial control was also conferred to the photo-patterning applications presented in this dissertation by influencing the degree of motility of gold nanorods (AuNRs) embedded in polymer matrices allowing them to self-assemble when the longitudinal plasmon of the incorporated nanostructures was excited; the patterns generated were quite robust and persisted for extended periods of time. Finally, the feature of spatial heating control was also conferred to catalysis. The Friedel-Crafts alkylation of anisole by benzyl chloride using spherical gold nanoparticles (AuNPs) supported on Nb2O5-based catalysts was performed at bulk temperatures below those necessary for the reaction to occur when using bare or modified Nb2O5; this was the result of the combination of bulk and localized plasmon heating produced -both- via plasmon excitation. This also demonstrates the possibility of using plasmon excitation as an alternative heat source in this type of reactions. By combining the plasmonic properties of metallic nanostructures with those granted by mesoporous materials, polymer matrices and Nb2O5-based materials it was possible to obtain light-activated systems endowed also with temporal control and wavelength control while preserving the original properties of each systems' components. Overall, the content of this thesis describes in detail the practical aspects of combining gold nanostructures with different materials and the rationale behind the development of systems with customized and controllable properties.

L'objectif est la mise au point d'une méthodologie de synthèse des nanoparticules d'or en présence du chitosane sous rayonnement permettant l'obtention d'objet de taille homogène et contrôlée. Dans ce but, nous mettrons l'accent sur l'étude des interactions entre les ions Au(III) et le chitosane en solution avant irradiation. En effet, la coordination entre des unités de glucosamine et l'ion Au(III) favorise la réduction de Au(III) en Au(0) et la formation de nanoparticules d'or. Cela est démontré clairement par l'étude de l'influence du pH sur la formation de nanoparticule lors du vieillissement des solutions d'HAuCl4 en présence de chitosane. Ce phénomène a été avance pour expliquer tout au moins partiellement, le mécanisme de la réduction des ions Au(III) en présence du chitosane sous rayonnement. Il s'agissait de définir si le mécanisme de réduction des ions Au(III) en ions Au(0) suivait un processus classique tels qu'il a été décrit dans les travaux de Belloni et de Henglein, ou si la présence de chitosane influe sur ce processus. L'élaboration des nanoparticules d'or en présence du chitosane utilisé comme agent stabilisant a été réalisée sous irradiation par faisceau d'électrons ou par rayonnement gamma. L'influence des paramètres de synthèse (rapport du [GLA]/[Au(III)], conditionnement des échantillons, effet de la dose d'irradiation, effet du débit de dose, rôle d'un piégeur de radicaux ou d'électrons solvatés) a ensuite été évaluée sur les propriétés caractéristiques des solutions de nanoparticules d'or (taille, charge, résonance plasmon de surface). L'activité catalytique des nanoparticules synthétisées a été testée vis-à-vis de la réaction de réduction du 4-nitrophénol en 4-aminophénol par NaBH4.Mots-clés : or, nanoparticules, chitosane, coordination, irradiation, faisceau d'électrons, rayonnement gamma, 4-nitrophénol. / The goal of this work is to develop a methodology for the synthesis of gold nanoparticles in the presence of chitosan under radiation to obtain a homogeneous object and controlled size. To reach this purpose, we will focus on the study of interactions between the ions Au(III) and chitosan in solution before irradiation. Indeed, the coordination between units of glucosamine and Au(III) promotes the reduction of Au(III) to Au(0) and the formation of gold nanoparticles. This is clearly demonstrated by the influence of pH on the formation of nanoparticles upon aging of HAuCl4 solutions in the presence of chitosan. This formulation has been used to explain the mechanism of reduction of Au(III) in the presence of chitosan in radiation. It was to define whether the reduction mechanism of ion Au(III) ions Au(0) followed a conventional process such as those described by the work of Belloni and Henglein, or if the presence of chitosan affects this process. The development of gold nanoparticles in the presence of chitosan used as a stabilizing agent was produced by the electron beam and gamma radiation. The influence of the synthesis parameters (report [GLA]/[Au (III)], sample conditioning, effect of irradiation dose, dose rate effect, role of a radical scavenger) on the characteristic gold nanoparticles was then evaluated (size, charge, surface plasmon resonance). The catalytic activity of these nanoparticles was tested towards the reduction reaction of 4-nitrophenol to 4-aminophenol by NaBH4.Keywords: gold, nanoparticles, chitosan, coordination, irradiation, electron beam, gamma radiation, 4-nitrophenol.

L’objectif de ce travail est de proposer un mécanisme réactionnel pour l’oxydation aérobie d’hydrocarbures lourds, alcanes et alcènes, catalysée par les nanoparticules d’or. La co-oxydation du stilbène et du méthylcyclohexane est utilisée comme réaction modèle afin de comprendre les nombreux mécanismes mis en jeu. Le criblage initial d’une large gamme de catalyseurs d’or nous permet de mettre en évidence des effets de support dans cette réaction et d’établir un cahier des charges bien défini pour l’élaboration d’un catalyseur de référence. Une méthode chimique simple est mise au point pour préparer un tel catalyseur. Ce catalyseur, optimisé pour les réactions en milieux organiques apolaires, est ensuite utilisé pour réaliser des études macrocinétiques en variant de nombreux paramètres expérimentaux : température, concentration des réactifs, quantité de catalyseur. Un intermédiaire réactionnel clef, l’hydroperoxyde de méthylcyclohexane, est identifié. Après dosage, l’étude de l’évolution de sa concentration au cours du temps dans les différentes conditions de réaction permet de valider le mécanisme réactionnel existant et de mieux comprendre l’importance de certaines étapes élémentaires / The aim of this work is to propose a mechanism for the gold-catalyzed aerobic oxidation of bulky hydrocarbons, alkanes and alkenes. The co-oxidation of stilbene and methylcyclohexane is used as a model reaction to study different mechanisms which can take place simultaneously. After an initial screening of different gold catalysts in this reaction, essential characteristics of a reference catalyst for organic reactions in apolar media are identified. Based on these requirements, a straight-forward, chemical bottom-up method is designed to prepare this reference catalyst. This catalyst is used for macro-kinetic studies of the co-oxidation by modifying experimental parameters, such as temperature, alkane/alkene ratio, and reactants initial concentration. One key reaction intermediate, 1-methylcyclohexyl hydroperoxide, is identified. After titration, following the evolution of the concentration of this intermediate with time under the various reaction conditions considered validates the existing mechanism and highlight the importance of some elementary steps of the co-oxidation

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

The need of purified biomolecules, such as proteins or antibodies, has required the biopharmaceutical industries to look for new recovering solutions to reduce time and costs of bioseparations. In the last decade, the emergent field of membrane chromatography has gained attention as possible substituent of the common used protein A affinity chromatography for bioseparations. In this scenario, gold nanoparticles can be used as means for offering affinity, mainly because of their biocompatible and reversible binding behavior, together with their high surface area-to-volume ratio, which offers a large number of binding sites. This work introduces a new procedure for purification of monoclonal antibodies based on polymeric membranes functionalized with gold nanoparticles. This novel approach shortens the process of purification by promoting selective binding of antibodies, while separating a mixture of biomolecules during a filtration process. The effects of gold nanoparticles and the surrounding ligand on the proteins adsorption and filtration are investigated. The results confirm that the functionalization helps in inducing a selective binding, preventing the non-selective one, and it also improves the selectivity of the separation process.

>Magister Scientiae - MSc / Nature through billions of years of trial and error has produced an immeasurable amount of natural systems like plants, birds and animals. The intelligence of nature is hidden in these natural systems and researchers are turning towards “Nature’s intelligence” to find inspiration and advance novelty in the development of nanomaterials. Gold nanoparticles (AuNPs) have unique optical, electronic and physicochemical features which has gained them popularity and widespread exploitation in various applications. The conventional methods used for AuNPs synthesis employs toxic chemicals which makes these NPs unsafe for biomedical applications. Hence, there is a search for new, ‘green’ and more cost effective methods for AuNPs synthesis. Plant extracts are regarded as a highly desirable system for nanoparticle synthesis due to their tremendous capability to produce a wide range of phytochemicals that can act as reducing agents. The main goal of this study was to synthesize AuNPs in a cost effective manner without the use of toxic chemicals in the synthesis process. Avocado seeds which are an agricultural waste by-product were used for the biosynthesis of AuNPs. The study reports on the synthesis optimization, characterization and activities of the biogenic AuNPs. The avocado seed extract mediated - AuNPs (AvoSE-AuNPs) were optimized by varying reaction parameters and characterized by UV-visible, Dynamic Light Scattering (DLS) and High Resolution Transmission Electron Microscopy (HRTEM), Zetasizer and Fourier Transform Infrared Spectroscopy (FTIR). The formation of AvoSE-AuNPs had an absorption maximum at 534 nm. HRTEM and DLS confirmed that the NPs were polydispersed and present in different shapes. The presence of phytochemical constituents on the AvoSE-AuNPs were confirmed by FTIR. Their potential antibacterial activity was tested on bacterial strains known to exhibit resistance to a number of current antibiotics. The catalytic activity of AvoSE-AuNPs was also assessed as a means to contribute to the development of new methods aimed at alleviating organic pollutants such as nitrophenols in the environment. The AvoSE-AuNPs demonstrated excellent catalytic activity in the reduction of 4-NP by NaBH4 as shown by the rapid decrease in the nitrophenolate absorption band at 400 nm and the appearance of new absorption band at 298 nm, revealing the formation of the 4-aminophenol. Furthermore, the rate constants calculated demonstrated that the reaction occurs faster in the presence AvoSEAuNPs. The AvoSE-AuNPs showed low significant cytotoxicity. Cell cycle analysis was conducted to further investigate the apparent exhibited toxicity of the AvoSE-AuNPs. The results showed that in both cell lines treated with AvoSE-AuNPs and AvoSE there was a ii | P a g e disruption in the regulation of cell cycle. Cell cycle analysis helped improve understanding of the low cytotoxicity observed by the MTT assay results. The results presented in this study clearly demonstrate the feasibility of using AvoSE for the synthesis of AuNPs. This study demonstrated that AvoSE mediated AuNPs synthesis is a greener alternative as it abides by the green chemistry principles. Furthermore, the study outcomes contributed to minimizing environmental pollution by finding use for agricultural waste and thus ultimately adding value to the field.

Metal and semiconducting nanocrystals have received a great deal of attention from fundamental scientists and application-oriented researchers due to their physical and chemical properties, which differ from those of bulk materials. Nanocrystals are essential building blocks in the development of nanostructured devices for energy conversion. Colloidal metals and metal chalcogenides have been developed for use as nanocrystal inks to produce efficient solar cells with lower costs. All high-performing photovoltaic nanocrystals contain toxic elements, such as Pb, or scarce elements, such as In; thus, the production of solution-processable nanocrystals from earth-abundant materials using environmentally benign synthesis and processing methods has become a major challenge for the inorganic semiconductor-based solar field. This dissertation, divided into two parts, addresses several aspects of these emerging challenges. The first portion of the thesis describes the synthesis and characterization of nanocrystals of antimony sulfide, which is composed of non-scarce and non-toxic elements, and examines their performance in photovoltaic devices. The effect of various synthetic parameters on the final morphology is explored. The structural, optical and morphological properties of the nanocrystals were investigated, and Sb2S3 nanocrystal-based solid-state semiconductor-sensitized solar cells were fabricated using different deposition processes. We achieved promising power conversion efficiencies of 1.48%. The second part of the thesis demonstrates a novel method for the in situ synthesis and patterning of nanocrystals via reactive inkjet printing. The use of low-cost manufacturing approaches for the synthesis of nanocrystals is critical for many applications, including photonics and electronics. In this work, a simple, low-cost method for the synthesis of nanocrystals with minimum size variation and waste using reactive inkjet printing is introduced. As a proof of concept, the method was used for the in situ synthesis of gold nanoparticles as a model system. Relatively monodisperse gold nanoparticles were produced. The size and shape of gold nanoparticles can be controlled by the gold precursor and surfactant concentration in the ‘ink.’ This approach can be extended to the synthesis of other nanocrystals and is thus a truly impactful process for the low-cost synthesis of materials and devices incorporating nanocrystals.

[EN] The contamination of water resources with many industrial, agricultural and other chemicals is one of the key environmental problems that humanity is facing nowadays. Despite the fact that they are usually present at very low concentration, they possess a significant risk to aquatic and human life. To address this issue many national and international institutions set different regulations to monitor and control the water quality. Currently, the monitoring of compounds included in official watch lists is conducted by chromatographic and mass spectroscopic methods. These techniques are approved as "gold standards" for analytical quantitation of organic residues in water. Although they are sensitive and reproducible, cannot be used on-site. The need of sampling and centralized laboratory measurements makes not only the overall cost high but lowering the efficiency of the analysis. Therefore, there is an urgent need to develop suitable field methods to facilitate the in situ measurements at a low cost. Biosensors are therefore an alternative technology that can provide sensitive results in a fast and affordable way. This thesis has focused on the development of a biosensor based on immunoassays and compact disk technology, for the multiplex detection of priority water contaminants. As the methods based on the immunorecognition events are challenging in terms of the selectivity and sensitivity, the major part of the thesis was the selection of the immunoreagents, assay form and procedure. For the detection part, gold nanostructures were selected as sensitive tags for signal enhancement. Therefore, different nanoparticles were studied in order to select the optimal size in terms of the signal enhancement, sensitivity and antibody amount used. Also, the assays performances with signal enhancement and without any amplification were evaluated. The best immunoassay was selected for developing the multiplexed assay. Furthermore, an approach to improve the readout sensitivity of microimmunoassays based on used of gold nanoparticles as both capture and detection species was demonstrated. The method is based on the performance of the immunorecognition event in a homogeneous mode and detection part in the heterogeneous format. Finally, representative water samples were analysed to confirm the applicability of the multi-residue assay. The analytical properties have been established for each methodology and the obtained results have been validated by comparison with reference techniques. The investigations carried out in this work, have resulted in new insights in immunoassay technique that could be useful for screening applications. / [ES] La contaminación de aguas superficiales causada por plaguicidas y productos industriales es actualmente, uno de los grandes problemas medioambientales. Aunque estas sustancias están presentes a niveles muy bajos, tienen efectos perjudiciales en el medio en general y especialmente en humanos. Por este motivo, diferentes instituciones han regulado los niveles de contaminantes en áreas de controlar de la calidad de las aguas, creando listas prioritarias de sustancias peligrosas y tóxicas para el medio ambiente. Actualmente, la monitorización de los contaminantes incluidos en las listas oficiales se realiza mediante técnicas cromatográficas y espectrometría. Estos métodos analíticos están aprobados como técnicas de referencia para la determinación de residuos orgánicos presentes en aguas naturales. A pesar de ser técnicas fiables, reproducibles y sensibles, los métodos cromatográficos no están exentos de inconvenientes. Este tipo de metodologías requiere una instrumentación costosa y una laboriosa preparación de muestra, que hacen que el análisis sea en general complejo. Por ello, el desarrollo de métodos analíticos alternativos que faciliten hacer medidas in-situ a bajo coste y con gran capacidad de trabajo es de gran utilidad. En este sentido, las técnicas inmunoquímicas tienen un gran potencial analítico ya que son en general sensibles y selectivas, se pueden utilizar en el lugar de la toma de muestra y tienen capacidad multianalito. Esta tesis se ha centrado en el desarrollo de un sistema biosensor, basado en la tecnología de disco compacto, para la detección multianalito de diversos contaminantes prioritarios en aguas naturales. Las limitaciones más críticas para el desarrollo de un biosensor multianalito mediante métodos inmunoquímicos son los relacionados con su sensibilidad y selectividad. Por lo tanto, una parte importante de la tesis se ha centrado en la selección de inmunoreactivos, formato y optimización de diferentes parámetros claves del ensayo. Una estrategia utilizada para aumentar la sensibilidad de los ensayos ha consistido en marcar la inmunoreacción con nanopartículas de oro. Para ello, se ha estudiado diferentes tipos (esféricas y cilíndricas) de distinto tamaño y se han comparado sus prestaciones analíticas (relación señal ruido, sensibilidad etc.) También, se han desarrollado inmunoensayos cuantitativos sin necesidad de amplificación de la señal. Por otro lado, se ha desarrollado una aproximación que hemos denominado "inmunocaptura" basada en el uso de nanopartículas de oro como especie de captura de analitos en disolución y que actúa como marcador de la inmunointeracción que tiene lugar en la fase sólida. Finalmente, se han analizado muestras de agua naturales dopadas con distintos niveles de los analitos objeto de estudio para evaluar la utilidad de las metodologías desarrolladas como herramienta de screening masivo en el área medioambiental. Los resultados obtenidos han sido comparados con los obtenidos mediante las técnicas de referencia. Las investigaciones realizadas han permitido desarrollar nuevos formatos de ensayo y conocimientos inmunoquímicos aplicados a la tecnología de disco compacto, aportando nuevas herramientas de screening que permiten la determinación simultánea de contaminantes en aguas naturales por debajo de las concentraciones establecidas en la normativa europea de calidad de agua. / [CA] La contaminació d'aigües superficials causada principalment per plaguicides i altres productes industrials és un dels grans problemes mediambientals actuals. Malgrat que aquestes substàncies estan presents en nivells molt baixos, tenen efectes perjudicials en humans i animals. Per aquest motiu, diferents institucions estatals han regulat els nivells de contaminants en àrees de control de la qualitat de l'aigua, creant llistes prioritàries de substàncies perilloses i tòxiques per al medi ambient. Actualment, la monitorització dels contaminants inclosos en les llistes oficials es realitza mitjançant tècniques cromatogràfiques i d'espectroscòpia de masses. Aquests mètodes analítics estan aprovats com a tècniques de referència per a la determinació de residus orgànics presents en aigües naturals. Malgrat ser tècniques fiables, reproduïbles i sensibles, els mètodes cromatogràfics no estan exempts d'inconvenients. Aquest tipus de metodologies requereix una instrumentació costosa i una laboriosa preparació de mostres que fan que l'anàlisi sigui, en general, complex. Per això, el desenvolupament de mètodes analítics alternatius que facilitin la possibilitat de fer mesures in-situ a baix cost i amb gran capacitat analítica és de gran utilitat. En aquest sentit, les tècniques inmunoquímiques tenen un gran potencial analític ja que són, en general, sensibles i selectives, es poden utilitzar en el lloc de presa de la mostra i tenen capacitat multianalit. Aquesta tesi s'ha centrat en el desenvolupament d'un sistema biosensor, basat en la tecnologia de disc compacte, per a la detecció multianalit de diversos contaminants prioritaris en aigües naturals. Les limitacions més crítiques per al desenvolupament d'un biosensor multianalit mitjançant mètodes inmunoquímics són sensibilitat i selectivitat. Per tant, una part important de la tesi es va centrar en la selecció de inmunoreactius, format i optimització de diferents paràmetres clau de l'assaig. La detecció es va dur a terme mitjançant l'ús de nanopartícules d'or com a marcadors de la inmunointeracció i amplificació de la senyal analítica. S'han estudiat diferents estructures d'or (esferes i cilindres) de diferents tamanys, i s'han comparat les seves prestacions analítiques (relació senyal-soroll, sensibilitat, etc.). També s'han desenvolupat immunoassaigs quantitatius sense necessitat d'amplificació del senyal. Per altra banda, s'ha desenvolupat una aproximació que hem denominat "inmunocaptura", basada en l'ús de nanopartícules d'or com a espècie de captura d'analits en dissolució i que actua com a marcador de la inmunointeracció que té lloc en la fase sòlida. Finalment, s'han analitzat mostres d'aigües naturals dopades amb diferents nivells dels analits objecte d'estudi per avaluar la utilitat de les metodologies desenvolupades com a eina de "screening" massiu en l'àrea mediambiental. Els resultats obtinguts han sigut avaluats per comparació amb els obtinguts mitjançant tècniques de referència. Les investigacions realitzades han permès desenvolupar nous formats d'assaig i coneixements inmunoquímics aplicats a la tecnologia de disc compacte, aportant noves eines de "screening" que permetin la determinació de contaminants en aigües naturals per sota dels límits de concentració establerts per les normes internacionals de la qualitat de l'aigua. / Dobosz, PD. (2017). Screening methodologies for the determination of water contaminant residues by compact disk technology [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/79548 / TESIS

One of the main subjects of this thesis is to design a novel synthetic route to covalently functionalize carbon nanotubes with various molecules in a non-toxic way on both surface and suspension. Functionalized carbon nanotubes are of great interest in the field of molecular electronics, materials science and nano-bio applications because of their remarkable structural, chemical and physical properties. First, the single-walled carbon nanotubes are functionalized with gold nanoparticles by the route, which involves silanization and copper-free click chemistry (SPAAC). We characterize the functionalized nanotubes through XPS, IR and Raman spectroscopic techniques to identify the surface attachment of molecules after each step. We observe a drastic change in homogeneity and functionalization density of single-walled carbon nanotubes with gold nanoparticles concerning solvent through TEM. Employing the same route, biomolecules such as fluorescent dyes and single-stranded DNA molecules are integrated with SWNTs. Fluorescence lifetime analysis of AF647 functionalized SWNTs is reduced compared to free dye due to the fluorescence quenching phenomenon of carbon nanotubes. Functionalized SWNTs are characterized with FLIM, SEM, and Raman for better correlation at the same area of interest. Furthermore, the nanotubes are resolved at the nanoscale level through STORM imaging technique with a limited photon budget. Single-stranded DNA molecules of different lengths are used to investigate the fluorescence quenching as they are distance-dependent. DNA-PAINT is engaged in imaging the functionalized SWNTs with an unlimited photon budget, overcoming STORM's challenge. Lastly, the route is transferred to surface-grown CNTs through the CVD technique, in which both the gold nanoparticles and fluorescent dyes are grafted with nanotubes selectively. CVD is carried out on different substrates Si/SiO2, quartz substrate and quartz coverslip for substrate functionalization. Catalyst deposition plays a significant role in not only the CVD growth but also in the lifetime analysis of the substrate functionalized nanotubes. We observe similar fluorescence quenching of nanotubes in the substrate compared with nanotubes functionalized in suspension. Surface-grown nanotubes in the optically transparent substrate can be resolved through STORM at the nanoscale level. In conclusion, we demonstrate a synthetic design to functionalize SWNTs which provides the possibility to be versatile and non-toxic. Moreover, we show that the nanotubes can be functionalized through this route homogeneously and selectively on both surface and suspension. This work lays the foundation for tailoring SWNTs with not only a wide range of molecules and to study their functional characteristics but also to carry out functionalization on different substrates for various applications.

Tato práce se zabývá syntézou sférických zlatých nanočástic pro biomedicínské aplikace. Zlaté nanočástice byly syntetizovány ekologicky nezávadnými metodami, kterým je věnována i značná část rešerše. Cílem bylo nasyntetizovat stabilní koloidní zlaté nanočástice vhodné pro různé biomedicínké aplikace zejména, pro in vivo a in vitro zobrazovací metody, kterých přehled je take obsažen v teoretické části práce. Také byl proveden test cytotoxicity, jelikož částice mají být použitelné pro in vivo aplikace. Částice byly dale charakterizovány metodami SEM, DLS a UV-VIS.