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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
281

Thermally Driven Technologies for Atmospheric Water Capture to Provide Decentralized Drinking Water

January 2020 (has links)
abstract: Limited access to clean water due to natural or municipal disasters, drought, or contaminated wells is driving demand for point-of-use and humanitarian drinking water technologies. Atmospheric water capture (AWC) can provide water off the centralized grid by capturing water vapor in ambient air and condensing it to a liquid. The overarching goal of this dissertation was to define geographic and thermodynamic design boundary conditions for AWC and develop nanotechnology-enabled AWC technologies to produce clean drinking water. Widespread application of AWC is currently limited because water production, energy requirement, best technology, and water quality are not parameterized. I developed a geospatial climatic model for classical passive solar desiccant-driven AWC, where water vapor is adsorbed onto a desiccant bed at night, desorbed by solar heat during the day, and condensed. I concluded passive systems can capture 0.25–8 L/m2/day as a function of material properties and climate, and are limited because they only operate one adsorption-desorption-condensation cycle per day. I developed a thermodynamic model for large-scale AWC systems and concluded that the thermodynamic limit for energy to saturate and condense water vapor can vary up to 2-fold as a function of climate and mode of saturation. Thermodynamic and geospatial models indicate opportunity space to develop AWC technologies for arid regions where solar radiation is abundant. I synthesized photothermal desiccants by optimizing surface loading of carbon black nanoparticles on micron-sized silica gel desiccants (CB-SiO2). Surface temperature of CB-SiO2 increased to 60oC under solar radiation and water vapor desorption rate was 4-fold faster than bare silica. CB-SiO2 could operate >10 AWC cycles per day to produce 2.5 L/m2/day at 40% relative humidity, 3-fold more water than a conventional passive system. Models and bench-scale experiments were paired with pilot-scale experiments operating electrical desiccant and compressor dehumidifiers outdoors in a semi-arid climate to benchmark temporal water production, water quality and energy efficiency. Water quality varied temporally, e.g, dissolved organic carbon concentration was 3 – 12 mg/L in the summer and <1 mg/L in the winter. Collected water from desiccant systems met all Environmental Protection Agency standards, while compressor systems may require further purification for metals and turbidity. / Dissertation/Thesis / Doctoral Dissertation Civil, Environmental and Sustainable Engineering 2020
282

Nanomaterials for Double-Stranded RNA Delivery

Lichtenberg, Stuart 01 January 2019 (has links)
RNA interference has enormous potential as a potent, specific, and environmentally friendly alternative to small molecule pesticides for crop protection. The use of exogenous double-stranded RNA offers flexibility in targeting and use in crops in which transgenic manipulation is not an option. The combination of RNAi with nanotechnology offers further advantages that are not available with dsRNA alone. In this work, I have evaluated several different combinations of nanomaterials and polymers for use in RNAi-based pest control systems. First, I have characterized the use of chitosan/dsRNA polyplex nanoparticles for gene knockdown using the model nematode Caenorhabditis elegans. Though chitosan/dsRNA polyplexes are equally as effective as naked dsRNA for gene knockdown on a concentration basis, these materials are assimilated into cells in a manner independent of dsRNA specific transport proteins. The mechanism of uptake is likely clathrin-mediated endocytosis. In addition, I identify a significant and yet unreported side-effect associated with chitosan exposure, the dysregulation of a major myosin isoform. Next, I have determined the efficacy of chitosan/dsRNA polyplex nanoparticles under different environmental conditions. The presence of inorganic ions (phosphate and nitrate) at realistic environmental concentrations does not alter the efficacy of the nanoparticles for gene knockdown, nor do they inhibit knockdown by naked dsRNA. These conditions did not cause any significant changes to the hydrodynamic diameter or zeta potential of the particles themselves between treatments. By contrast, a pH higher than six and the presence of natural organic matter significantly reduce the efficacy of the nanomaterials at gene knockdown but leave knockdown by naked dsRNA unaffected. Though some changes in polyplex size are observed in the pH treatments, these changes are comparatively small, and particles remain well within the size that can be ingested by C. elegans. At pH 8, the charge of the particles is effectively neutral. Similarly, concentrations of natural organic matter >2.5 mg/L cause a charge reversal of the particles, from strongly cationic to strongly anionic. Large aggregates are also visible in each of these treatments. Lastly, I characterize the efficacy of a suite of different polymer and solid core nanomaterials for dsRNA delivery, similar to the above. Poly-L-lysine, poly-L-arginine, Ge-doped imogolite, and poly-L-arginine-citrate coated Au nanoparticles all fail to cause any appreciable knockdown in the same C. elegans reporter system. Uptake of the polymers was exceedingly poor, and though the Au particles appear to have been ingested, there is no evidence of significant gene knockdown. Furthermore, poly-L-arginine caused significant injury to the mouthparts of C. elegans exposed to these materials. Layered double-hydroxide nanoparticles were successful at gene knockdown, and appear to function slightly better than naked dsRNA alone, and were translocated in C. elegans in a similar fashion to naked dsRNA. Taken together, these findings aid in the development of safe and effective RNAi biological control agents.
283

Анализа квантних механизама транспорта присутних у мемристивним уређајима на бази наноматеријала / Analiza kvantnih mehanizama transporta prisutnih u memristivnim uređajima na bazi nanomaterijala / Analysis of quantum transport mechanisms in nanometarial based memristive devices

Samardžić Nataša 24 December 2016 (has links)
<p>Истаживања у оквиру докторске дисертације имају за циљ да пруже допринос дубљем разумевању физичких механизама присутних код мемристора, с обзиром да у стручној литератури и даље постоје отворена питања везана за кључни процес који индукује мемристивни ефекат у материјалу. Као функционални материјал за меморије на бази промене валенце, на ком се испитује мемристивни ефекат, одабран је титанијум диоксид јер се већ показао као добар кандидат за резистивно-прекидачке меморије. Експериментални резултати показују ефекат квантизације проводности за ТiО2 мемристоре, што захтева развијање и примену модела балистичког транспорта за описивање електричних карактериристика узорка.</p> / <p>Istaživanja u okviru doktorske disertacije imaju za cilj da pruže doprinos dubljem razumevanju fizičkih mehanizama prisutnih kod memristora, s obzirom da u stručnoj literaturi i dalje postoje otvorena pitanja vezana za ključni proces koji indukuje memristivni efekat u materijalu. Kao funkcionalni materijal za memorije na bazi promene valence, na kom se ispituje memristivni efekat, odabran je titanijum dioksid jer se već pokazao kao dobar kandidat za rezistivno-prekidačke memorije. Eksperimentalni rezultati pokazuju efekat kvantizacije provodnosti za TiO2 memristore, što zahteva razvijanje i primenu modela balističkog transporta za opisivanje električnih karakteriristika uzorka.</p> / <p>Research topics in this PhD thesis aims to provide contribution in deeper<br />understanding of physical mechanisms which drives resistive-switching<br />mechanism in memristors, as existing literature provides open questions for<br />key mechanism processes which influences memristive effect in materials. In<br />order to test response of Valance Change Memories, TiO2 nanomaterial was<br />used as the functional layer, as this material was already shown suitable for<br />these applications. Measured results show conductance quantization effect<br />for TiO2 based memristors, which requiers ballistic transport model for<br />interpretation of electrical response of the device.</p>
284

Characterization of Liquid-Phase Exfoliated Two-Dimensional Nanomaterials Derived from Non-van der Waals Solids

January 2020 (has links)
abstract: Liquid-phase exfoliation (LPE) is a straightforward and scalable method of producing two-dimensional nanomaterials. The LPE process has typical been applied to layered van der Waals (vdW) solids, such as graphite and transition metal dichalcogenides, which have layers held together by weak van der Waals interactions. However, recent research has shown that solids with stronger bonds and non-layered structures can be converted to solution-stabilized nanosheets via LPE, some of which have shown to have interesting optical, magnetic, and photocatalytic properties. In this work, two classes of non-vdW solids – hexagonal metal diborides and boron carbide – are investigated for their morphological features, their chemical and crystallographic compositions, and their solvent preference for exfoliation. Spectroscopic and microscopic techniques are used to verify the composition and crystal structure of metal diboride nanosheets. Their application as mechanical fillers is demonstrated by incorporation into polymer nanocomposite films of polyvinyl alcohol and by successful integration into liquid photocurable 3D printing resins. Application of Hansen solubility theory to two metal diboride compositions enables extrapolation of their affinities for certain solvents and is also used to find solvent blends suitable for the nanosheets. Boron carbide nanosheets are examined for their size and thickness and their exfoliation planes are computationally analyzed and experimentally investigated using high-resolution transmission electron microscopy. The resulting analyses indicate that the exfoliation of boron carbide leads to multiple observed exfoliation planes upon LPE processing. Overall, these studies provide insight into the production and applications of LPE-produced nanosheets derived from non-vdW solids and suggest their potential application as mechanical fillers in polymer nanocomposites. / Dissertation/Thesis / Doctoral Dissertation Chemistry 2020
285

Nanobezpečnost a současné trendy v hodnocení rizik nanočástic / Nanosafety and the Current Trends in the Risk Assessment of Nanoparticles

Valovič, Stela January 2020 (has links)
This diploma thesis deals with the current state of nanosafety. The aim of this paper was to review and critically analyze approaches to facilitate the risk assassment of nanomaterials. In the first part it provides an overview of the most important methods and software tools that are used in this field. Methods were analyzed against a set of relevant criteria. Criteria include consideration of exposure, life cycle and physicochemical properties, transparency, applicability and the field of application. Different criteria were chosen for the software tools. Based on results, a new approach was suggested. The approach takes the form of a diagram based on questions. The purpose of the suggested approach is to recommend the most relevant method, tool or their combination to assess the safety of a nanomaterial depending on known characteristics. The approach was also implemented in a software tool.
286

Synthesis of new nanomaterials based on porphyrins and graphene for elaboration of sensitive and selective DNA biosensors / Synthèse de nouveaux nanomatériaux basés sur des porphyrines et du graphène pour l'élaboration de biocapteurs d'ADN sensibles et sélectifs

Wang, Yaqiong 09 October 2017 (has links)
La conception et le développement de biocapteurs pour la détection directe de biomarqueurs dans un échantillon de fluide biologique constituent un véritable défi dans la recherche pour leur application dans le système de point de soins en diagnostic. Mon projet est axé sur l'élaboration d'une nouvelle plateforme de décomposition biologique composée de graphène qui présente une surface électroactive et spécifique élevée permettant de greffer de nombreux biomolécules avec des métalloporphyrines en tant que nouveau marqueur redox pour suivre le processus de reconnaissance biologique obtenu dans le cas d'un capteur d'ADN. Le concept sera de démontrer que les métalloporphyrines où le potentiel d'oxydo-réduction pourrait être contrôlé par la nature des ions métalliques pourraient être appliquées dans une plate-forme de biocapteurs électrochimique multidétection. L'association de la métalloporphyrine avec le graphène offrira de nombreux avantages, comme la promotion de la réaction de transfert d'électrons et ayant une grande surface pour l'immobilisation des protéines. La détection de la cible présente sera réalisée suite à l'activité redox des métalloporphyrines greffées à la surface. Nous avons déjà synthétisé différentes métalloporphyrines modifiées et caractérisées par des techniques habituelles de spectrométrie telles que la RMN, les UV et la MS. Le biocapteur d'ADN a été construit par le composite de graphène et métalloporphyrine et sonde d'ADN comme biorécepteur suivant l'approche d'attachement covalent et l'optimisation de la construction de biocapteur pour améliorer la stabilité et la reproductibilité. Et nous avons déjà fait une détection de l'ADN cible par diverses méthodes électrochimiques, y compris la voltamétrie cyclique, la voltampérométrie à onde carrée et la spectroscopie d'impédance. Cette stratégie a été réalisée d'abord avec la porphyrine Mn insérée puis généralisée à divers complexes métalliques pour une approche multidétection. Parallèlement, les nanomatériaux hybrides combinant les caractéristiques du graphène (haute conductivité et grande surface spécifique) et des porphyrines (propriétés physiques et chimiques et capacité de transfert d'électrons), tels que la tétraphénylporphyrine portant un et quatre groupes carboxyliques nommés H₂TPP-nCP (n = 1, 4) et la tétraphénylporphyrine incorporant du manganèse (III) (MnTPP-1CP) ont été synthétisés avec succès. L'interaction entre H₂TPP-nCP (n = 1, 4) et l'oxyde de graphène chimiquement réduit (CRGO) a été étudiée dans mon travail de thèse. Pour étudier les propriétés caractéristiques des nanomatériaux préparés, la microscopie électronique à balayage (MEB), la microscopie à force atomique (AFM), les spectres UV-visible, les spectres infrarouges à transformée de Fourier (FT-IR) et les spectres de photoélectrons X. Afin d'éliminer l'absorption non spécifique, la modification de l'électrode par le PEA a également été appliquée et obtenir une excellente application pour la détection de la cible d'ADN. / The design and development of biosensors for direct detection of biomarkers in biological fluid sample is real challenge in research for their application in point of care system in diagnostic. My project is focus on the elaboration of a new platform for biological detaction composed of graphene which exhibits a high electroactive and specific surface suitable for grafting numerous biomoleculer with metalloporphyrins as a novel redox marker for following biological recognition process obtained in the case of DNA sensor. The concept will be to demonstrate that the metaloporphyrines where there redox potential could be controlled by the nature of metal ions could be applied in multidetection electrochemical biosensor platform. The association of metalloporphyrin with graphene will offer numerous advantages, as promoting electron transfer reaction and having a large surface for protein immobilization. The detection of target present will be performed following redox activity of the metalloporphyrins grafted on the surface. We have already synthesized various modified metalloporphyrins and characterizatized by usual spectrometry techniques such as NMR, UV and MS. The DNA biosensor has been constructed by the composite of graphene and metalloporphyrin and DNA probe as bioreceptor following covalent attachment approach and optimization of the biosensor construction for improving stability and reproducibility. And we have already done some detection of DNA Target by various electrochemical methods including cyclic voltammetry, square wave voltammetry and impedance spectroscopy. This strategy was performed firstly with on Mn inserted porphyrin and then generalized to various metal complex for multidetection approach. Meanwhile, the hybrid nanomaterials which combined the features of both graphene (high conductivity and large specific surface area) and porphyrins (physical and chemical properties and electron transfer ability), such as tetraphenylporphyrin bearing one and four carboxylic group named H₂TPP-nCP(n=1, 4) and tetraphenylporphyrin incorporating manganese (III) (MnTPP-1CP) were successfully synthesized. The interaction modes between H₂TPP-nCP(n=1, 4) and chemically reduced graphene oxide (CRGO) was studied in my thesis work. To investigate the characteristic properties of as-prepared nanomaterials, scanning electron microscopy (SEM), atomic force microscopy (AFM), UV-visible spectra, Fourier Transform infrared spectra (FT-IR), X-ray photoelectron spectra (XPS). In order to eliminate the non-specific absorption, the modification of the electrode by monolayer PEA was also applied and obtain excellent application for the detection of DNA target.
287

Détection électrochimique en puce microfluidique : importance des transducteurs nanocarbonés / Electrochemical detection in microfluidic devices : study of carbon-based nanomaterials as transducers

Zribi, Bacem 26 February 2016 (has links)
Dans le cadre d’une thèse en cotutelle qui a démarré en Janvier 2013, j'ai développé des biopuces ultra-sensibles pour la détection de maladies infectieuses (Tuberculose et Hepatite C). Ce sujet, qui combine recherche fondamentale et recherche appliquée dans pour le diagnostic précoce de maladies, avait pour but la détection rapide d’espèces chimiques fortement diluées dans un liquide biologique. Cette détection se fait de manière électrochimique, grâce à l’utilisation des nanomatériaux carbonés innovants (feuillets de graphène, nanotubes de carbone (NTCS)) qui sont dotés d’une conductivité électronique élevée. J’intègre ces nanomatériaux par des procédés de micro/nanofabrication sur des électrodes de travail dans des cellules microfluidiques. J'ai démontré qu'en combinant un haut flux et un transducteur en NTCs qu'il est possible d'augmenter de 3 ordres de grandeur la sensibilité de détection dans la chambre fluidique (article soumis à LoC). J'ai aussi étudié par spectroscopîe d'impédance la nature du transfert des charges entre l'électrolyte et la graphène (2ème article en cours de rédaction). Mon doctorat a donc validé une technologie innovante pour les biocapteurs miniaturisés à ADN, avec un fort potentiel de valorisation, dans le domaine de la santé et de l’environnement. / As part of my thesis under joint supervision between UPS and Sfax Universities which started in January 2013, I developed ultra-sensitive biochips for the detection of infectious diseases (Tuberculosis and Hepatitis C). This subject, which combines basic and applied research for the early detection of diseases, aimed rapid detection of highly diluted chemical species such as DNA in a biological fluid. This detection is done electrochemically, through the use of innovative carbon nanomaterials (graphene layers, carbon nanotubes (NTCS)) which are provided with a high electron conductivity. I have integrated these nanomaterials by micro / nano-fabrication processes on working electrodes in microfluidic cells. I demonstrated that by combining a high flow and a that CNTs as transducer, the sensitivity of detection in the fluid chamber can be increased by 3 orders of magnitude (Article submitted to Lab on Chip journal). I also studied by impedance spectroscopy the nature of the charge transfer between the electrolyte and the graphene (2nd article being drafted). My PhD has validated an innovative technology for miniaturized biosensors DNA, with a strong development potential in the field of health and the environment.
288

Synthèse de nanoparticules de dioxyde de titane par pyrolyse laser et leur application en photocatalyse / Synthesis of titanium dioxide nanoparticles by laser pyrolysis : application in photocatalysis

Bouhadoun, Sarah 01 October 2015 (has links)
Le dioxyde de titane suscite un grand intérêt dans le domaine de la photocatalyse. Cependant, il n'utilise que la composante UV du flux solaire soit 4-5 % de l'énergie disponible. Un objectif de cette thèse est d'élaborer un matériau capable d'absorber dans le visible tout en restant actif sous lumière UV. Des nanoparticules de dioxyde de titane modifiées avec de l'or et/ou de l'azote ont été synthétisées par pyrolyse laser. Les poudres obtenues ont été caractérisées systématiquement par différentes techniques physico-chimiques (analyse ICP-AES), structurales (DRX), morphologiques et texturales (MET, MEB, BET), optiques (Spectroscopie UV-Visible) et électroniques (XPS, RPE et TRMC). Les particules présentent une structure cristalline majoritairement anatase, avec une taille moyenne de l'ordre de 7-10 nm. Leur efficacité photocatalytique a été évaluée par HPLC vis-à-vis de la dégradation d'acides carboxyliques (C1-C4) sous lumière UV et Visible. Les résultats photocatalytiques obtenus sur un polluant modèle (l'acide formique) ont révélé que sous UV le TiO2 préparé par pyrolyse laser est nettement plus actif que la référence commerciale. La modification à l'or améliore encore l'efficacité en facilitant le transfert de charge, alors que le dopage à l'azote introduit des sites de recombinaison provoquant donc un effet négatif. Ces résultats ont été corrélés à la dynamique des porteurs de charge étudiée par TRMC (Time Resolved Microwave Conductivity). La combinaison des deux élèments Au et N montre une efficacité proche de la référence commerciale, tout en introduisant une activité dans le visible. Dans le cas des acides à plus longue chaîne, la photoactivité des différents photocatalyseurs est proche de la référence commerciale sous lumière UV, mais reste très limitée dans le visible. La compréhension des mécanismes de dégradation a été abordée par la Résonance Paramagnétique Electronique (RPE). / Titanium dioxide is the most widely used photocatalyst due to its amazing properties. However, TiO2 is activated by UV radiation which represent about 4-5 % of solar light. One aim of this work is to shift the adsorption of TiO2 to the visible range while maintaining photoactivity under UV. Therefore N-doped and gold modified TiO2 nanoparticles have been synthesized in one step by laser pyrolysis. The materials have been characterized; their photocatalytic activity was evaluated by the degradation of carboxylic acids (C1-C4) under both UV and Visible irradiation. When dealing with the decomposition of formic acid under UV light, all samples exhibit a higher activity compared to commercial P25. Modification with Au increases the reaction rate by enhancing charge separation, while N-doped sample are less efficient due to recombination centers induced by Nitrogen. These results were correlated to the dynamic of electron/hole pairs studied by TRMC (Time Resolved Microwave Conductivity). Moreover, the combination of Au and N showed an efficiency similar to commercial P25 under UV irradiation associated to photoactivity in the visible range. In the case of C2-C4 acids, photocatalytic performances of all photocatalysts are similar to commercial P25 under UV, but very weak under visible light. Degradation mechanisms were investigated by ESR (Electron Spin Resonance).
289

Passive and active surfaces to reduce fouling of membranes and membane modules

January 2019 (has links)
abstract: This dissertation investigates the mechanisms that lead to fouling, as well as how an understanding of how these mechanisms can be leveraged to mitigate fouling. To limit fouling on feed spacers, various coatings were applied. The results showed silver-coated biocidal spacers outperformed other spacers by all measures. The control polypropylene spacers performed in-line with, or better than, the other coatings. Polypropylene’s relative anti-adhesiveness is due to its surface free energy (SFE; 30.0 +/- 2.8 mN/m), which, according to previously generated models, is near the ideal SFE for resisting adhesion of bacteria and organics (~25 mN/m). Previous research has indicated that electrochemical surfaces can be used to remove biofilms. To better elucidate the conditions and kinetics of biofilm removal, optical coherence tomography microscopy was used to visualize the biofouling and subsequent cleaning of the surface. The 50.0 mA cm-2 and 87.5 mA cm-2 current densities proved most effective in removing the biofilm. The 50.0 mA cm-2 condition offers the best balance between performance and energy use for anodic operation. To test the potential to incorporate electrochemical coatings into infrastructure, membranes were coated with carbon nanotubes (CNTs), rendering the membranes electrochemically active. These membranes were biofouled and subsequently cleaned via electrochemical reactions. P. aeruginosa was given 72h to develop a biofilm on the CNT-coated membranes in a synthetic medium simulating desalination brines. Cathodic reactions, which generate H2 gas, produce vigorous bubbling at a current density of 12.5 mA cm-2 and higher, leading to a rapid and complete displacement of the biofilm from the CNT-functionalized membrane surface. In comparison, anodic reactions were unable to disperse the biofilms from the surface at similar current densities. The scaling behavior of a nanophotonics-enabled solar membrane distillation (NESMD) system was investigated. The results showed the NESMD system to be resistant to scaling. The system operated without any decline in flux up to concentrations 6x higher than the initial salt concentration (8,439 mg/L), whereas in traditional membrane distillation (MD), flux essentially stopped at a salt concentration factor of 2x. Microscope and analytical analyses showed more fouling on the membranes from the MD system. / Dissertation/Thesis / Doctoral Dissertation Civil, Environmental and Sustainable Engineering 2019
290

Gated nanomaterials as delivery platform for the treatment of inflammatory disorders

García Fernández, Alba 08 November 2020 (has links)
[ES] La presente tesis doctoral titulada "Nanomateriales con puertas moleculares como plataforma de liberación controlada de fármacos para el tratamiento de desórdenes inflamatorios" se centra la preparación y evaluación de nanomateriales híbridos orgánico-inorgánicos, basados en nanopartículas mesoporosas de sílice, para la liberación controlada de fármacos en aplicaciones biomédicas, en concreto en el campo de la inflamación. En primer lugar se describe un nanomaterial para la liberación controlada del inhibidor de caspasa-1, VX-765, aprovechando la acumulación preferencial de las nanopartículas en las zonas inflamadas. En concreto, se han preparado nanopartículas mesoporosas de sílice, cargadas con el fármaco VX-765 y funcionalizadas covalentemente con ¿-poli-L-lisina que actúa como puerta molecular. La actividad anti-inflamatoria del material se ha comprobado tanto in vitro, en el modelo celular de monocitos THP-1, como in vivo en ratones en un modelo de inflamación de bolsa de aire. Los resultados muestran la acumulación preferente de las nanopartículas en las zonas inflamadas así como un aumento del efecto terapéutico del fármaco que se atribuye a las ventajas que ofrece la encapsulación. Se concluye que las nanopartículas mesoporosos de sílice con puertas moleculares podrían ser una herramienta importante para el desarrollo de nuevas estrategias terapéuticas en el campo de la inflamación. Basándonos en los resultados obtenidos, en el capítulo cuatro se describe un sistema de liberación controlada para el tratamiento de la inflamación pulmonar aguda como terapia alternativa que permita la administración directa de fármacos a los pulmones. Se ha preparado un nanosistema basado en nanopartículas mesoporosas de sílice cargadas con el glucocorticoide dexametasona y funcionalizadas covalentemente con una puerta molecular peptídica que reconoce el receptor del factor de necrosis tumoral 1 (TNFR1), que a su vez actúa como agente diana para la acumulación preferente en macrófagos pro-inflamatorios. La actividad terapéutica del sistema se ha corroborado en ensayos in vitro en macrófagos pro-inflamatorios, e in vivo en un modelo de ratón de inflamación pulmonar aguda. Se ha comprobado la acumulación preferente de las nanopartículas en los pulmones inflamados, así como la mejora del efecto terapéutico de la dexametasona en la reducción del daño pulmonar, minimizando los efectos adversos asociados a la administración del fármaco libre. Con todo ello se concluye que las nanopartículas mesoporosas de sílice pueden ser utilizadas para el tratamiento de la inflamación pulmonar aguda pudiendo ser una herramienta útil para superar las limitaciones de los tratamientos actuales. Finalmente, se describe otro sistema de liberación controlada de fármacos para inflamación pulmonar aguda. En este caso, se aborda el uso de un nuevo inhibidor del inflamasoma, QM-378, como terapia farmacológica alternativa. Con el objetivo de potenciar la administración directa en los pulmones inflamados, el QM-378 se encapsula en nanopartículas mesoporosas de sílice funcionalizadas con la puerta molecular peptídica que reconoce TNFR1. La acumulación preferente de las nanopartículas en los pulmones inflamados queda demostrada a través de los ensayos de biodistribución, así como la mejora del efecto terapéutico del QM-378 en la reducción del daño pulmonar, debido a las ventajas de la encapsulación en un nanosistema dirigido. Con todo ello se concluye que el QM-378 es un buen candidato para el tratamiento de la inflamación pulmonar aguda, y que su encapsulación en las nanopartículas ofrece una administración pulmonar directa y controlada, consiguiéndose así una mejora en el perfil terapéutico del fármaco. La conclusión principal de la presente tesis doctoral es que el desarrollo de nanomateriales mesoporosos de sílice para la liberación controlada de fármacos se presenta como un / [CAT] La present tesi doctoral titulada "Nanomaterials amb portes moleculars com a plataforma d'alliberament controlat de fàrmacs per al tractament de desordres inflamatoris" se centra en la preparació i avaluació de nanomaterials híbrids orgànic-inorgànics, basats en nanopartícules mesoporoses de sílice, per a l'alliberament controlat de fàrmacs en aplicacions biomèdiques, en concret en el camp de la inflamació. En primer lloc, es presenta un nanomaterial per a l'alliberament controlat de l'inhibidor de caspasa-1, VX-765, aprofitant que les nanopartícules s'acumulen preferencialment en les zones inflamades. S'han preparat nanopartícules mesoporoses de sílice, carregades amb VX-765 i funcionalitzades covalentment amb ¿-poli-L-lisina com a porta molecular. L'activitat anti-inflamatòria del material s'ha comprovat tant in vitro, en el model cel·lular de THP-1, com in vivo en ratolins en un model d'inflamació de bossa d'aire. Els resultats mostren la acumulació preferent de les nanopartícules en les zones inflamades així com un augment de l'efecte terapèutic del fàrmac, atribuÏt als avantatges que ofereix l'encapsulació. Es conclou que les nanopartícules mesoporoses de sílice amb porta molecular podrien ser una eina important per al desenvolupament de noves estratègies terapèutiques en el camp de la inflamació. Basant-nos en els resultats obtinguts, en el capítol quatre es presenta un sistema d'alliberament controlat per al tractament de la inflamació pulmonar aguda com a teràpia alternativa que permet l'administració directa de fàrmacs als pulmons. S'ha preparat un nanosistema basat en nanopartícules mesoporoses de sílice carregades amb el glucocorticoide dexametasona i funcionalitzades amb la unió covalent de una porta molecular peptídica que reconeix el receptor del factor de necrosi tumoral 1 (TNFR1), que al seu torn actua com a agent diana per a la acumulació preferent en macròfags pro-inflamatoris. L'activitat terapèutica del sistema dissenyat s'ha corroborat en assajos in vitro en macròfags pro-inflamatoris, i in vivo en un model de ratolí d'inflamació pulmonar aguda. S'ha comprovat la acumulació preferent de les nanopartícules en els pulmons inflamats a través d'assajos de biodistribució, així com la millora de l'efecte terapèutic de la dexametasona en la reducció de la lesió pulmonar minimitzant els efectes adversos associats a l'administració del fàrmac lliure. Amb tot això es conclou que les nanopartícules mesoporoses de sílice poden ser utilitzades per al tractament de la inflamació pulmonar aguda ja que poden ajudar a superar les limitacions dels tractaments actuals. Finalment es mostra també un sistema d'alliberament controlat de fàrmacs per a inflamació pulmonar aguda. En aquest cas, es descriu l'ús d'un nou inhibidor de l'inflamasoma, QM-378, com a teràpia farmacològica alternativa al tractament de la inflamació descontrolada en la inflamació pulmonar aguda. Amb l'objectiu de potenciar l'administració directa en els pulmons inflamats, el QM-378 s'encapsula en les nanopartícules mesoporoses de sílice funcionalitzades amb la porta molecular péptidica que reconeix TNFR1. La acumulació preferent de les nanopartícules en els pulmons inflamats queda demostrada a través dels assajos de biodistribució, així com la millora de l'efecte terapèutic del QM-378 en la reducció de la inflamació pulmonar, atribuït als avantatges de l'encapsulació en un nanosistema dirigit. Amb tot això es conclou que el QM-378 és un bon candidat per al tractament de la inflamació pulmonar aguda, i que la seua encapsulació en les nanopartícules ofereix una administració pulmonar directa i controlada aconseguint-se així una millora en el perfil terapèutic del fàrmac. La conclusió principal és que el desenvolupament de nanomaterials mesoporosos de sílice per a l'alliberament controlat de fàrmacs es presenta com una estratègia amb molt potencial en el camp de les / [EN] This PhD thesis entitled "Gated nanomaterials as delivery platform to manage inflammatory disorders" is focused on the design, synthesis and evaluation of hybrid organic-inorganic nanomaterials using mesoporous silica nanoparticles, for controlled drug release in biomedical applications, specifically in the field of inflammation. In a fist step, we present a new nanodevice for the controlled delivery of VX-765, a caspase 1 inhibitor, which takes advantage of the intrinsic passive targeting effect of the nanoparticles to inflamed tissues. In particular, mesoporous silica nanoparticles loaded with the drug VX-765 and functionalized with ¿-poly-L-lysine (acting as gatekeeper) have been prepared. The anti-inflammatory activity of the prepared nanodevice has been evaluated both in vitro, in the cellular model of monocytes THP-1, and in vivo using air pouch mouse as model of inflammation. The results showed the preferential accumulation of the nanoparticles in the inflamed tissue, as well as an increase in the therapeutic effect of the entrapped drug. As conclusion, gated mesoporous silica nanoparticles constitute an important tool for the development of new therapeutic strategies in the inflammatory field. Based on the previous results presented, a drug delivery system for the treatment of acute lung injury is described in chapter four as alternative therapy that allow the direct delivery of drugs into the lungs. Mesoporous silica nanoparticles has been prepared, loaded with the glucocorticoid dexamethasone and capped with a peptide gatekeeper that recognizes the receptor of tumour necrosis factor 1 (TNFR1), which also targets the pro-inflammatory macrophages. The therapeutic activity of the designed nanoparticles has been studied in vitro in pro-inflammatory macrophages, and in vivo in an acute lung injury mouse model. The preferential accumulation of the nanoparticles in the inflamed lungs has been corroborated through biodistribution assays, as well as the ability to enhance the dexamethasone therapeutic effect by the reduction of lung injury and minimizing the undesired side effects associated of the free drug administration. As conclusion, gated mesoporous silica nanoparticles can be used for the treatment of acute lung injury and represent a potential tool to overcome the limitations of current treatments. Finally, a drug delivery system for acute lung injury is also presented. In this case, we use the novel inflammasome inhibitor QM-378 as pharmacological alternative therapy to the treatment of uncontrolled inflammation in acute lung injury. With the aim of enhancing the direct drug delivery in lungs, QM-378 is encapsulated in mesoporous silica nanoparticles capped with a peptidic gate that recognizes TNFR1. The preferential accumulation of nanoparticles to inflamed lungs has been also corroborated through biodistribution assays. An enhancement of the therapeutic effect of QM-378 by reducing lung inflammation is demonstrated, due to the advantages of drug encapsulation in a targeted-lung nanosystem. As conclusion, the QM-378 is a suitable candidate for acute lung injury treatment, and its encapsulation in mesoporous silica nanoparticles offers a direct lung drug delivery thus improving the therapeutic profile of the drug. The principal conclusion from this PhD thesis is that the preparation of mesoporous silica nanoaprticles for drug delivery is presented as potential strategy in the field of inflammatory disorders. / García Fernández, A. (2019). Gated nanomaterials as delivery platform for the treatment of inflammatory disorders [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/132694 / TESIS

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