Dissertations / Theses on the topic 'Inorganic Nanoparticles, Organic Particles'

A simple and facile way to the fabrication of nano to micro scale organic-inorganic hybrid particles was demonstrated. A well known “template-assisted approach” was chosen for the preparation of these hybrid particles, in which the inorganic material of interest is templated against the template particles. A series of colloidal template particles including, polystyrene, poly (vinylcaprolactam) and poly (N-isopropylacrylamide) was used for the deposition of a variety of metal oxides/hydroxide nanoparticles. A classical surfactant free co-polymerization process was employed for the synthesis of these template particles. To facilitate the deposition of inorganic nanoparticles in subsequent steps, these colloidal particles were functionalized with the suitable functional groups. For this purpose, polystyrene particles were synthesized in the presence of acetoacetoxyethylmethacrylate (AAEM) co-monomer. Similarly, poly (vinylcaprolactam) and poly (N-isopropylacrylamide) particles were functionalized by adding AAEM and acrylic acid co-monomers, respectively, during their synthesis. It is thought that an effective interaction between these functionalities of employed template and metal oxide/hydroxide precursors is the driving force for the fabrication of organic-inorganic hybrid particles. A number of metal oxide/hydroxide nanoparticles including ZnO, TiO2, Ta2O5 and In(OH)3 were deposited on the surface of polystyrene colloidal particles. A systematic variation in the employed reaction conditions allowed a modulation in size, shape, morphology, shell thickness and inorganic contents of resulting hybrid particles. Similar effect of the employed Indium isopropoxide concentration on the morphology of PS-In(OH)3 hybrid particles was observed. In the case of PS-TiO2 and PS-Ta2O5 only core-shell morphology was observed. However, suitable surface chemistry and careful selection of reaction parameters allowed the deposition of as much thick as 130 nm TiO2/Ta2O5 shell on the polystyrene core. In addition, a controlled manipulation of the shell thickness with the employed concentration of inorganic salt was observed. Polystyrene colloidal particles coated with a high refractive index material such as TiO2, were employed as building blocks for the fabrication of self assembled colloidal crystals. The variation in particle size and TiO2 content of employed building blocks allowed the manipulation in stop band position and band width of resulting photonic structures. Furthermore, PS-ZnO hybrid particles with raspberry-like morphology were exploited as carrier for ZnO nanoparticles into a host polymer matrix to achieve a nanocomposite material. In addition, fabrication of a series of closed, intact and mechanically robust hollow spheres, composed of pure and mixed metal oxides was demonstrated. The removal of polystyrene core from PS-TiO2 and PS-Ta2O5 hybrid particles by chemical or thermal treatment resulted into the hollow TiO2 and Ta2O5 spheres, respectively. Templating of PVCL colloidal particles against ZnO nanoparticles was shown and variation in physical properties of the resulting hybrid microgels as a function of the loaded amount of ZnO nanoparticles was demonstrated. PVCL-ZnO hybrid microgels showed the temperature sensitivity of the template particles and the UV-absorbing property of the loaded ZnO nanoparticles. It was demonstrated that these hybrid materials can effectively be used in the preparation of a transparent UV-shielding material. In addition, the deposition of preformed and functionalized quantum dots (CdTe) on the surface of PNIPAm microgel particles was explored and a manipulation in the fluorescent properties of loaded quantum dots as a result of temperature induced swelling and deswelling of microgel template was investigated. It was found that the fluorescence of deposited quantum dots can be switched to “ON” or “OFF” by changing the temperature of the surrounding media. These hybrid particles are envisioned to be used in the fabrication of temperature nanosensors.

In recent years, polymer-inorganic nanoparticle compositions have been a subject of considerable interest in order to achieve desired chemical, physical properties and mechanical properties. In this study a polymer nanocomposites have been prepared by incorporating silica nanoparticles (~20 nm) as fillers into poly(ethylene oxide) matrix. The composites of poly(ethylene oxide) and silica nanoparticles were prepared by solution blending. The product composites were powders. The thermal properties of the composites were investigated using the Differential Scanning Calorimetry. The Nuclear Magnetic Resonance (13C solid state, T1ρ), Atomic Force Microscopy, X-ray diffraction and Fourier Transform Infrared Spectroscopy were used to investigate the effect of the nanoparticles on the polymer matrix. The results suggest that the silica nanoparticles were reasonably well dispersed in the PEO 35K. The dispersion was accompanied by slightly reduced the crystallinity. However, with increasing the SiO2 nanoparticles the aggregation Phenomenon appears. Moreover, with increase in the MW of the PEO to 100K the dispersion of the nanoparticles decreased and aggregation phenomenon is observed even at lower of SiO2 contents.

Thesis (Ph. D.)--Ohio State University, 1998.
Advisor: John J. Lannutti, Dept. of Materials Science and Engineering. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

A robust synthetic routes to crafting conjugated polymer (CP) grafted semiconducting nanocrystal (NC) nanocomposites with the intimate contact between these two semiconducting constituents was introduced. The architecture of semiconducting nanocrystals (i.e., CdSe, and CdTe) was controlled by tuning the fraction of mobile bifunctional ligands, yielding azide functionalized CdSe nanorods, CdTe tetrapods, and CdSe tetrapods after conversion of bromide group into azide moiety. Subsequently, ethynyl end-functionalized poly(3-hexylthiophene) (P3HT) were grafted onto NC surfaces via catalyst-free click chemistry. The intimate contact between P3HT and semiconducting NCs rendered the effective dispersion of NCs in nanocomposites, and facilitated their efficient electronic interaction as can be confirmed by photoluminescence spectroscopy. The success of coupling reaction was confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. Furthermore, the effect of size and shape of semiconducting NCs and the types of functional ligands on the photovoltaic device performance was studied.

Substances that consist of nano-scale fillers dispersed in a polymer matrix are known as polymer-nanocomposites (PNCs). These materials are appealing since they have high potentials for applications, due to their mechanical, electrical, and thermo electrical properties. A common problem associated with PNCs is that the nano-fillers have a tendency to aggregate into clusters and form phase separated domains, which cause the desired properties of the system to either diminish or vanish all together. Hairy nanoparticles (HNPs) can avoid the issue of agglomeration that is commonly encountered by conventional PNCs. When polymer chains are grafted to a nanoparticle, and the coverage is high, the nanoparticles have decreased inter-particle interactions which allows for enhanced dispersion and mixing into a polymer matrix. By tailoring the architecture (functionalization of polymer chains, degree of polymerization, grafting density) of HNPs, it is possible to control the final properties of the system. An in depth study was carried out to investigate the effects of hairy-nanoparticle architecture on the resulting properties of the material itself. Atom transfer radical polymerization and living anionic polymerization were used to synthesize the polymer chains, of the HNP systems, while various instrumental methods including differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were utilized to study the physical ageing affects and self-assembly of these systems. #88ABW-2015-4971

Nanotechnology aims at the design, synthesis, characterization and application of materials and devices on the nanoscale. Nanoparticles are defined as materials with the three dimensions in the space less than 100 nm. They possess properties hugely different from the corresponding macroscopic materials. Their peculiarities depend on the reduced size, shape, composition and interface, all aspects that can be controlled during the synthesis. Moreover, nanoparticles can act as platforms for assemble well-defined multifunctional structures able to perform varied tasks. Nanoparticles can be made by inorganic materials and by soft materials. In the currently work a wide range of nanoparticles have been designed, synthesized and characterized for various purposes. In chapter 4 we propose simple and cheap strategy to develop multi-stimuli sensitive perylene diimide (PDI) molecules to create new smart materials by self-assembly. In chapter 5 we report synthesis of designed molecule that self-assemble in nanoparticles in biocompatible environment without any dramatic decrease of fluorescence brightness. In chapter 6 a similar work has been repeated with commercial fluorophores. Detection of chemical and biological agents plays a fundamental role in environmental and biomedical sciences. In chapter 7 small gold nanocluster functionalised with seven thiols in has been studied in presence active pharmaceutical ingredient (API). In chapter eight we try to increase melanin radiation protection activity both increasing number of stable free radicals and introducing oxidative ion transition metal. We have chosen Fe(III) and Mn(III) to increase oxidative ability and Zn(II), that do not possess oxidative ability as reference. We used 4-amino-TEMPO to increase number of stable free radicals.

Pour pallier le problème d’efficacité de la plupart des médicaments disponibles sur le marché aujourd’hui, lié à des manques de spécificité et de solubilité, notamment dans le cadre du traitement du cancer, la nanomédecine, via les nanoparticules présente une alternative de grande importance. Dans ce domaine, les nanoparticules de silice ont récemment attiré une énorme attention de la part des scientifiques. Cependant, des problèmes d’élimination liés à la solidité du matériau entravent aujourd’hui sa traduction clinique. Afin d’élucider cette problématique, nous présentons, dans cette thèse, l’utilisation de nanoparticules de silice hybrides dont l’une est mésoporeuse et l’autre sous forme de nanocapsule dépourvue de porosité. Les particules qui sont sphériques ont été préparées en incorporant un groupement imine dans leur charpente afin de les rendre sensibles au pH bas, sachant que les tissus cancéreux présentent une certaine acidité par comparaison aux tissus sains. Les matériaux préparés se montrent particulièrement sensibles aux milieux acides similaires aux conditions dans les milieux cancéreux. Dans le même temps, ces particules exposent une bonne stabilité en milieu à pH neutre similaire aux conditions physiologiques. Des études in vitro réalisées avec la particule mésoporeuse sur une lignée de cellule cancéreuse issue du sein humain démontrent une bonne et rapide internalisation. De plus, lorsque le matériau est chargé avec un médicament hydrophobe très puissant utilisé dans le traitement du cancer du sein, le système en résultant indique une efficacité de grande ampleur en tuant une forte majorité des cellules cancéreuses, contrairement au système basé sur la particule non cassable et au médicament isolé. Parallèlement, les nanocapsules chargées avec un autre agent anticancéreux se montrent particulièrement cytotoxiques vis-à-vis de cellules cancéreuses très communes et qui l’internalisent de manière très rapide
To overcome the limitations of most of the drugs avaible nowadays on the market due to their lack of solubility and specifity in cancer treatment for instance, nanomedicine plays an emerging role as an alternative. In that field, nanoparticles are endowed with several advantages, leading them to be highly considered for drug delivery systems preparation. In this respect, silica nanoparticles have recently a great deal of attention from the scientists. Nevertheless, some issues related to the in vivo elimination of silica materials represent the main obstacle impeding their clinical translation. To elucidate this problematic, we report, in this thesis, the use of breakable hybrid organosilica nanoparticles where one is mesoporous and the other one consists in a nanocapsule without porosity. Such materials have been prepared by incorporating an imine-based linker in the particles framework in order to make them pH-responsive. The advantage of the pH sensitivity relies on the fact that cancerous media present certain acidity as compared to those healthy. The particles exhibit a high pH sensitivity where, at low pH, they fully break down, while a good stability is observed in physiological conditions. Furthermore, in vitro studies performed with a drug delivery system based on the mesoporous particle and a highly hydrophobic drug show a remarkable efficiency towards a cancer cell line from human breast, which moreover, rapidly internalises the material. The nanocapsule loaded with a hydrophilic drug also demonstrates a fast internalisation towards a commonly used cancer line which does not resist to the system and thus dies by a very high rate

Nanoparticles are used as electrocatalysts due to their large surface area-to-volume ratios. Most studies of nanoparticle electrocatalysis are performed on collections of particles on a support, which represent ensemble average behavior influenced by spatial distribution of the nanoparticles. Therefore, recent emphasis has been placed on analyzing electrocatalytic behavior of single particles. The focus here is to develop carbon ultramicro- and nanoelectrode platforms for studying the electrocatalytic properties of single metal nanoparticles. Ultramicroelectrodes were prepared using chemical vapor deposition of carbon in pulled quartz capillaries. Electrode diameters were determined by cyclic voltammetry. Electrodes were modified using a soft nitriding technique to enable immobilization of platinum nanoparticles through reduction of H2PtCl6 using NaBH4. Cyclic voltammetry was used to determine the presence of platinum particles through characteristic peaks associated with Pt oxide formation and reduction. Ultimately, these electrodes could be used to analyze single uncapped nanoparticles to understand the electrochemical properties of single nanoparticles.

Detection of organic molecules present on the surface of dust particles is important in homeland security, agriculture, and several other applications. The research presented reports the ability of the aerosol mass spectrometer (AMS) to detect molecules on the surface of dust particles without detecting the particle core. Experiments were carried out to detect semi-volatile organic compounds adsorbed onto the surface of particulates without interference from the dust particle core. Methyl salicylate, oleic acid, and organophosphorus pesticides such as Malathion were detected on the surface of particles representative of dust-type materials. Zeolite powders were used as aerosol support, representative of a typical silica mineral aerosol present in the atmosphere. Mass spectral fingerprint information was gained by first directly detecting atomized species to record their clean electron impact mass spectrum. This facilitated detection during later experiments of organic molecules coated on an inorganic support. Spectra obtained give mass spectrometric signatures of molecules coated on inorganic particles without detection of the particle core. An important feature of the AMS is the ability to equate an ion rate detected in the mass spectrometer to a mass concentration of a given chemical species in a sample using its ionization efficiency. Based on an average inlet flow rate of 1.2 cm 3sec -1 the ionization efficiencies obtained were 5.89x10-5, 1.15x10-6, and 1.62x10-5 for Malathion, methyl salicylate, and oleic acid, respectively. These experiments and the results obtained show that detection and characterization of organic species adsorbed onto inorganic dust particles are possible at µg m-3 concentrations using the AMS.

xviii, 174 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.
Hybrid nanoscale complexes incorporate the attributes of organic and inorganic components to yield novel multifunctional materials. Because the individual components themselves and the combinations used can be widely varied to tune the properties of the resulting complex, the potential for new properties and practical applications is nearly limitless. However, widespread use of these materials relies on appropriate design, synthesis and characterization strategies to ensure proper function and compositional integrity. This dissertation describes the chemistry of these hybrids, made possible by combining organic ligands, inorganic nanoparticles, and metal ions, and the interesting optical and spectroscopic properties associated with the hybrid nanomaterials. Organic ligands containing Bunte salt and acyclic malonamide functionalities were attached to gold nanoparticles to produce colorimetric sensors for lanthanide ion detection. Bunte salt functionality stabilizes the gold core and malonamide functionality offers selective and sensitive lanthanide ion binding. The binding interaction controls a nanoparticle cross-linking event that changes the color of the nanoparticle solution, resulting in visual, colorimetric lanthanide ion detection. Next, the concentration of malonamide ligand was diluted and replaced with a diluent ligand yielding nanoparticles stabilized with a mixed ligand composition. The mixed ligand environment makes the optical response of the colorimetric sensor reversible. Furthermore, the use of Bunte salt ligands during nanoparticle synthesis has allowed the investigation of the role of reducing agent on nanoparticle stability. In addition to exploring interactions pertaining to gold nanoparticle complexes, a new approach to sensitize europium ion luminescence was developed by fabricating a zinc oxide/europium complex. A molecular linker permits simultaneous zinc oxide nanoparticle functionalization and trivalent europium binding in order to tether the europium ion close to the nanoparticle surface. The zinc oxide nanoparticle can then act as an inorganic antenna, transferring energy to the europium ion and enhancing its luminescence. Finally, a strategy was developed to synthesize bifunctional bicyclic malonamides. Synthesis of these ligands allows the enhanced f-block ion binding affinity of bicyclic malonamides to be incorporated into functional materials to compare their performance to our previously prepared acyclic malonamide hybrid complexes. This dissertation includes my previously published and co-authored materials.
Committee in charge: Darren Johnson, Chairperson, Chemistry; James Hutchison, Advisor, Chemistry; Catherine Page, Member, Chemistry; Michael Haley, Member, Chemistry; Barbara Roy, Outside Member, Biology

The interaction of the inorganic nanoparticles (GdYVO4:Eu, d 2 nm) and organic carbocyanine dye 3,3’ -diethyloxa-carbocyanine iodide (DiOC2) has been studied spectrophotometrically. The formation of complexes of dye molecules with spherical nanoparticles GdYVO4:Eu in aqueous solutions of cationic dye DiOC2 was found. It is shown that nanoparticle GdYVO4:Eu can form a complex with 5-10 molecules of the cationic dye DiOC2 which leads to the decrease in the intensity of the absorption and luminescence spectra of the dye in aqueous solution. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35005

La presente tesis doctoral se ha enfocado en el diseño y la síntesis de un nuevo tipo de materiales compuestos basados en metal-organic frameworks (MOFs) o covalent-organic frameworks (COFs) y nanopartículas inorgánicas y el uso de estos materiales compuestos para la catálisis heterogénea. En el primer capítulo se introduce la familia de materiales compuestos dispersos en/sobre diferentes materiales haciendo especial énfasis en aquellos construidos con MOFs y COFs. En el capítulo 2 se presentan los objetivos generales de la tesis doctoral. En el capítulo 3 se muestran los resultados del artículo “The influence of the MOF shell thickness on the catalytic performance of composites made of inorganic (hollow) nanoparticles encapsulated into MOFs” publicado en 2016 en la revista Catalysis Science & Technology. En el mismo se reporta la encapsulación de nanopartículas huecas de Platino y Paladio en el ZIF-8 formando así una serie de materiales compuestos en los cuales el espesor de la cáscara de ZIF-8 era modulada de manera sistemática. En el capítulo 4, nanopartículas híbridas de tipo núcleo-coraza de Au/CeO2 dispersadas en microesféras de UiO-66 han sintetizados usando el método se atomización por secado con flujo continuo. Las propiedades catalíticas combinadas en una única partícula de los nanocristales de CeO2 y Au y la capacidad protectora de las microesféras porosas de UiO-66 hacen que estos materiales compuestos muestren resultados interesantes como catalizadores para la reacción de reducción de monóxido de Carbono. (T50 = 72 °C; T100 = 100 °C) con alta reusabilidad. Los resultados obtenidos han sido incluidos en el artículo. “Core-shell Au/CeO2 nanoparticles supported in UiO-66 beads exhibiting full CO conversion at 100 °C” publicado en la revista Journal of Materials Chemistry A en 2017. Finalmente, en el capítulo 5, hemos demostrado que usando un método en dos pasos se pueden funcionalizar COFs confinando en ellos nanopartículas. La reacción directa entre el 1,3,5-tris(4-aminofenil)benceno y el 1,3,5-benzenetricarbaldehído en presencia de una variedad de nanopartículas metalícas o de óxidos de metal resulta en la encapsulación de estas nanopartículas en un polímero amorfo de iminas-enlazadas con forma de esfera. El Post-tratamiento de estas esferas con ácido acético en reflujo conduce a la obtención de esferas cristalinas de COFs basados en iminas. Además materiales compuestos basados en COF y nanopartículas de Au y Pd han demostrado ser catalíticamente activas. Estos resultados han sido publicados en el artículo “Confining Functional Nanoparticles into Colloidal Imine-Based COF Spheres by a Sequential Encapsulation-Crystallization Method” publicado en la revista Chemistry a European Journal en 2017.
The present PhD Thesis has been dedicated to the design and synthesis of a new type of composites of metal-organic frameworks (MOFs) or covalent-organic frameworks (COFs) with inorganic nanoparticles (iNPs) and the use of these composites for heterogeneous catalysis. In the first chapter, we introduce the family of composites made by supporting iNPs on/in different materials, focusing on those constructed with MOFs and COFs. Then, the general objectives of the Thesis are described in Chapter 2. Chapter 3 shows the results in “The influence of the MOF shell thickness on the catalytic performance of composites made of inorganic (hollow) nanoparticles encapsulated into MOFs”, Catalysis Science & Technology (2016). Herein, we report the encapsulation of hollow Pt or Pd nanoparticles (NPs) into ZIF-8, making a series of composites in which the ZIF-8 shell thickness has been systematically varied. By using these composites as catalysts for the reduction of 4-nitrophenol and Eosin Y, we show that the MOF shell thickness plays a key role in the catalytic performance of this class of composites. In Chapter 4, hybrid core-shell Au/CeO2 NPs dispersed in UiO-66 shaped into microspherical beads are created using the spray-drying continuous-flow method. The combined catalytic properties of nanocrystalline CeO2 and Au in a single particle and the support and protective function of porous UiO-66 beads make the resulting composites show good performances as catalysts for CO oxidation (T50 = 72 °C; T100 = 100 °C) and recyclability. The results are included in the manuscript entitled “Core-shell Au/CeO2 nanoparticles supported in UiO-66 beads exhibiting full CO conversion at 100 °C”, Journal of Materials Chemistry A (2017). Finally, in Chapter 5, we demonstrated a two-step method that enables imparting new functionalities to COFs by nanoparticle confinement. The direct reaction between 1,3,5-tris(4-aminophenyl)benzene and 1,3,5-benzenetricarbaldehyde in the presence of a variety of metallic/metal-oxide nanoparticles resulted in the embedding of the nanoparticles in amorphous and nonporous imine-linked polymer organic spheres. Post-treatment reactions of these polymers with acetic acid under reflux led to crystalline and porous imine-based COF- hybrid spheres. Interestingly, porous imine-based COF-hybrids with Au and Pd NPs were found to be catalytically active. These results have been reported in the publication entitled “Confining Functional Nanoparticles into Colloidal Imine-Based COF Spheres by a Sequential Encapsulation-Crystallization Method”. Chemistry a European Journal (2017).

Thesis (Ph.D)--Industrial and Systems Engineering, Georgia Institute of Technology, 2010.
Committee Chair: Tsukruk, Vladimir; Committee Member: Bucknall, David; Committee Member: Kalaitzidou, Kyriaki; Committee Member: Shofner, Meisha; Committee Member: Tannenbaum, Rina. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Dans le contexte énergétique actuel, la conception de panneaux photovoltaïques efficaces représente une des solutions pour pallier à la pénurie prochaine des énergies fossiles. Cependant, les phénomènes de dégradation de l’encapsulant, un des matériaux passifs du panneau, sont une des origines de la baisse de rendement des modules. L’objectif de ce travail de thèse a été de concevoir, caractériser et évaluer les différentes propriétés de nouveaux encapsulants hybrides organique-inorganique contenant des ressources renouvelables. Ainsi, trois matériaux ont été élaborés à partir d’alcool polyvinylique (PVA), de résines terpéniques et de charges minérales (silice ou argile (Bentonite)). Un premier matériau comprenant PVA, résine et silicates, dans lequel composantes organique et inorganique sont liées par des liaisons covalentes fortes (hybride de classe II), a conduit à des stabilités thermiques et photochimiques, et des propriétés optiques et barrières à la vapeur d’eau et à l’oxygène, similaires à celles des encapsulants actuels.L’introduction de nanoparticules de silice dans un mélange PVA/résine via des liaisons faibles a ensuite fourni un matériau hybride de classe I aux propriétés barrières à la vapeur d’eau satisfaisantes mais avec des transparences optiques insuffisantes pour une utilisation comme encapsulant, du fait de l’agrégation des nanoparticules. Enfin, malgré une transparence optique devant être encore optimisée, un matériau hybride de classe I constitué de PVA, de résine et de Bentonite a conduit à de bonnes propriétés thermiques, photochimiques, barrières à la vapeur d’eau et surtout d’excellentes propriétés barrières à l’oxygène, ce qui ouvre de nouvelles perspectives (emballage alimentaire…)
In the current energetic context, the design of efficient solar photovoltaic panels represents one of the solutions to overcome the coming fossil fuels shortage. However, degradation phenomena of the encapsulant, one of the passive materials of the panel, have been evidenced as one of the reasons of the performance decrease. The aim of this PhD research work was to design, characterize and assess the different properties of more environment-friendly new hybrid organic-inorganic encapsulants. In this way, three materials have been developed using polyvinyl alcohol (PVA), terpenic resins and mineral fillers (silica or clay(Bentonite)). A first material including PVA, resin and silicates, in which both organic and inorganic networksare linked through strong covalent bonds (class II hybrid material), led to thermal and photochemical stabilities, and water vapor and oxygen barriers properties similar to those of commercial encapsulants.Dispersion of silica nanoparticles into PVA/terpenic resin mixture through weak bond then provided a class Ihybrid material showing rather good water vapor barrier properties but optical transmittance too low to beused as an encapsulant, due to the aggregation of the nanoparticles. Finally, despite an optical transparency that should be optimized, a class I hybrid material made of PVA, resin and Bentonite showed promisingbehavior with good thermal, photochemical and water barrier properties and remarkable oxygen barrier properties, which opens up new prospects in the field of food packaging

Proteins are a diverse category of biomolecules with great therapeutic potential. Intracellular delivery of proteins can augment the deficient activities of dysfunctional or poorly expressed innate proteins and therefore represents a promising strategy to treat the associated diseases. One major barrier to intracellular protein delivery is the translocation of the protein across the cellular membrane. Endocytosis provides an important pathway for protein nanocarriers to enter cells across the plasma membrane. However, the cargo protein must then promptly escape from the endosomes to avoid degradation in the lysosome and to exert its cellular function. Previously, we reported a cationic lipid-coated magnesium phosphate nanoparticle (LPP) system for intracellular protein delivery. The intracellular delivery of catalase, an antioxidant enzyme, by LPP protected MCF-7 cells from a lethal level of exogenous H2O2 and lowered the reactive oxygen species (ROS) levels in EA.hy926 cells. These findings prompted us to further develop LPP to evaluate its protein delivery in animals. Two categories of LPP formulations, catalase-encapsulated (CE) LPP and catalase-complexed (CC) LPP, were successfully prepared by a modular approach. Catalase-encapsulated liposomes (CE LP) were prepared by hydrating a thin-film of lipids with catalase solution followed by extrusion. However, extrusion of CE LP resulted in substantial loss of catalase activity. Catalase-complexed liposomes (CC LP) were prepared by first extruding cationic liposomes with a LIPEX extruder and then mixing with catalase solution. The resultant CC LP was much smaller than CE LP and preserved all the catalase activity. Magnesium phosphate nanoparticles (MgP NP) were prepared by the microemulsion precipitation technique. CE LP or CC LP were mixed with MgP NP to yield LPP formulations (CE LPP or CC LPP, respectively). The formulations were then rendered isotonic with glucose (5% w/v). Transmission electron microscopy (TEM) confirmed the proposed structure of LPP comprising a shell of lipid bilayers with a core of MgP NP. Furthermore, TEM showed drastic morphological changes of LPP formulations at acidic pH, consistent with an osmotic explosion. The LPP formulations were administered by intravenous or intranasal routes to CD-1 mice. LPP formulations of fluorescently labeled catalase distributed substantially into the lung following intranasal administration, whereas intravenous administration of the same formulations caused catalase distribution mainly into the liver. In addition, intranasal administration of both the LPP formulations yielded higher pulmonary catalase activity and lowered the ROS levels in the healthy lung compared to free catalase solution. Based on these results, LPP’s antioxidant effects were further evaluated in mice with lipopolysaccharide-induced acute lung injury (ALI). Lack of LPP distribution into the lung following intranasal administration indicated that intranasal dosing did not deliver catalase substantially into inflamed lungs. In corroboration, the inflammatory biomarker tumor necrosis factor-alpha (TNF-α) remained unchanged after intranasal dosing of LPP formulations. Intratracheal dosing of LPP formulations delivered the fluorescently labeled catalase deep into the lung and significantly reduced TNF-α production in the inflamed lungs compared to free catalase solution. CC LPP, which was smaller and which better preserved catalase activity than CE LPP, showed greater intrapulmonary catalase activity compared to CE LPP in both healthy and inflamed lungs. Taken together, LPP represents a promising nanocarrier for intracellular protein delivery.

In this thesis, the potential functional interactions of gold nanoparticles with organic, hybrid, inorganic and biological systems have been investigated. Nanoparticles with varying sizes have been synthesized following different preparation methods. Molecular-like (D < 2 nm), highly fluorescent few-atoms clusters were prepared by a slow reduction of gold salts in organic solvent, yielding a colloidal solution that can be easily redispersed in a variety of solvents and matrices, including sol-gel silica and a hybrid copolymer. The emission wavelength has a lifetime in the ns and can be tuned from the near UV to the whole visible range by adjusting the reaction parameters, and the luminescence is stable for months both in intensity and wavelength. Use of alternative precursors and solvents, influence of reaction temperature and purification methods are all currently being investigated, together with potential application as biolabels and sensitizers for rare-earth-based optical amplifiers. Uncapped nanoparticles with 3 nm < D < 10 nm were obtained in situ in fluorinated polyimides via thermal reduction-precipitation with the concurrent matrix imidization. The doping profile, monitored with RBS analyses, can be easily varied both for thick (30 mm) and thin (< 1 mm) film samples. The selective permeability properties that are typical of polyimides suggest potential employment as both optical and electic gas sensors, and the first measurements are now underway. Eventually, 10 nm nanoparticles were synthesized with the traditional Turkevich citrate method, capped with streptavidin and used to functionalize DNA origami structures. Liquid cell AFM technique allows to image the effectiveness of the proposed method for positioning nanoscopic objects with nm resolution thanks to the peculiar design features of these DNA-based structures. The specific interest is here related to the possibility of using them as lego-like building blocks for nanoelectronics, and the focus is at present centered on the self-induced or externally directed organization of the functionalized origami on substrates. At present, self-assembly on patterned surfaces is being studied together with AFM electrophoresis, but new interesting strategies are being proposed on a daily basis as further interesting origami peculiarities emerge.

A magnetic functionalization of microcrystalline MOF particles was realized using magnetic iron oxide particles. Such magnetic MOFs can be separated using a static magnetic field after use in catalytic processes and heated by an external alternating magnetic field to trigger desorption of encaged drug molecules
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich

A magnetic functionalization of microcrystalline MOF particles was realized using magnetic iron oxide particles. Such magnetic MOFs can be separated using a static magnetic field after use in catalytic processes and heated by an external alternating magnetic field to trigger desorption of encaged drug molecules.
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

One of the most challenging goals in nanoparticle research is to develop successful protocols for the large-scale, simple and possibly low-cost preparation of morphologically pure nanoparticles with enhanced properties. The work presented in this thesis was focused on the synthesis, characterisation and testing of magnetic nanoparticles and their potential applications. There are a number of magnetic nano-materials prepared for specific applications such as metal oxide nanoparticles encapsulated with various porous materials including Fe₃O₄/Fe₂O₃ coated with soft bio-organic materials such as glycol chitosan and bovine serum albumin and hard materials such as silica (SiO₂) and zinc sulphide (ZnS). The preparation of these materials was achieved principally by bottom-up methods with different approaches including micro-emulsion, precipitation, electrostatic and thermolysis processes. The thesis also presents the uses of various analytical techniques for characterising different types of nano-materials including Attenuated Total Reflection Fourier Transformer Infrared Vibrational Spectroscopy (ATR-FTIR), Ultraviolet Visible- Near Infrared (UV-Vis-NIR) Spectroscopy, Zeta Potentiometric Surface Charge Analysis, Superconducting Quantum Interference Device (SQUID) and Vibration Sample Magnetometry (VSM) for magnetic analysis and powder X-Ray Diffraction (XRD) for crystallographic pattern analysis. There are many applications of magnetic nanoparticles, including nano-carriers for biological and catalytic reagents. The magnetic nanoparticles can facilitate separation in order to isolate the carriers from solution mixtures as compared to many inefficient and expensive classic methods, which include dialysis membrane, electrophoresis, ultracentrifugation, precipitation and column separation methods. There are six key chapters in this thesis: the first chapter introduces the up-to-date literature regarding magnetic nano-materials. The uses of magnetic nano-materials in drug binding and for protein separation are discussed in the second and third chapters. The fourth chapter presents the use of magnetic nanoparticle in conjunction with a photo-catalytic porous overlayer for the photo-catalytic reduction of organic molecules. The fifth chapter describes different analytical techniques used for the characterisation of nanoparticles and the underlying principles and the experimental details are also given. The sixth chapter summarises the results and provides an overview of the work in a wider context of future applications of magnetic nanoparticles.

[ES] La presente tesis doctoral titulada "Nanodispositivos mesoporosos híbridos funcionalizados con enzimas para detección, liberación controlada y comunicación molecular" se centra en el diseño, preparación, caracterización y evaluación de distintos nanodispositivos híbridos orgánico-inorgánicos utilizando como soporte nanopartículas tipo Janus de oro y sílice mesoporosa, que se equipan con enzimas, especies fluorescentes y puertas moleculares. Como conclusión general, los estudios realizados muestran que la incorporación de enzimas sobre nanopartículas permite introducir funciones de reconocimiento con alta especificidad y diseñar nanodispositivos avanzados para distintas finalidades. La combinación de nanopartículas híbridas con grupos orgánicos como puertas moleculares, efectores enzimáticos y especies cromo- fluorogénicas o fármacos puede resultar muy versátil; y se espera que los resultados obtenidos puedan inspirar el desarrollo de nuevos materiales inteligentes con aplicación en distintas áreas como la nanomedicina y la detección de moléculas de interés.
[CAT] La present tesi doctoral titulada "Nanodispositius mesoporosos híbrids funcionalitzats amb enzims per a detecció, alliberació controlada i comunicació molecular" es centra en el disseny, preparació, caracterització i avaluació de distints nanodispositius híbrids orgànic-inorgànics utilitzant com a suport nanopartícules tipus Janus d'or i sílice mesoporosa, que s'equipen amb enzims, espècies fluorescents i portes moleculars. Com a conclusió general, els estudis realitzats mostren que la incorporació d'enzims sobre nanopartícules permeten introduir funcions de reconeixement amb alta especificitat i dissenyar nanodispositius avançats per a distintes finalitats. La combinació de nanopartícules híbrides amb grups orgànics com portes moleculars, efectors enzimàtics i espècies cromo-fluorogèniques o fàrmacs pot resultar molt versàtil; i s'espera que els resultats obsessos inspiren el desenvolupament de nous materials intel·ligents amb aplicació en distintes àrees com la nanomedicina i la detecció de molècules d'interés.
[EN] This PhD thesis entitled "Enzyme-functionalized hybrid mesoporous nanodevices for sensing, controlled release and molecular communication" is focused on the design, synthesis, characterization and evaluation of several hybrid organic-inorganic nanodevices using Janus gold-mesoporous silica nanoparticles as scaffolds, equipped with enzymes, fluorescent species and molecular gates. In conclusion, these studies show that the incorporation of enzymes on nanoparticles allows to introduce recognition capabilities with high specificity and to design advanced nanodevices for different purposes. The combination of hybrid nanoparticles with organic groups such as molecular gates, enzymatic effectors and chromo-fluorogenic species or drugs can be very versatile; and we hope that the obtained results inspire the development of new smart materials with application in different areas such as nanomedice and sensing.
Llopis Lorente, A. (2019). Enzyme-functionalized hybrid mesoporous nanodevices for sensing, controlled release and molecular communication [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/117612
TESIS

Orientadores: Ana Flavia Nogueira, Jonas Gruber
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
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Resumo: Este trabalho consistiu no desenvolvimento e caracterização de materiais para aplicação em células fotovoltaicas híbridas. No Capítulo I, uma introdução geral sobre o funcionamento e estado da arte de células solares, e sobre as propriedades de polímeros condutores e nanopartículas inorgâncias é apresentada. O Capítulo II contém os objetivos deste trabalho. No Capítulo III, foram investigados novos polímeros condutores, baseados na combinação de unidades fluoreno com unidades tiofeno e/ou benzeno. As propriedades fotofísicas, eletroquímicas e de transporte de cargas foram caracterizadas, e esses polímeros foram então combinados com um derivado solúvel de fulereno (PCBM) e os compósitos formados (heterojunção) foram aplicados em células solares com configuração ITO | PEDOT:PSS | Heterojunção | LiF | Al. A seguir, foram sintetizadas nanopartículas de CdSe com diferentes tamanhos, usando um método descrito na literatura. Essas partículas foram caracterizadas por medidas de absorção e emissão, voltametria cíclica (VC), difração de Raios-X (DRX) e microscopia eletrônica de transmissão (TEM), conforme apresentado no Capítulo IV. Os polímeros investigados inicialmente foram combinados com as nanopartículas de CdSe, e esses materiais foram utilizados na montagem de células solares híbridas. De modo geral, os dispositivos apresentaram valores baixos de fotocorrente, o que foi atribuído ao fato de as nanopartículas inorgânicas não transportarem elétrons de forma efetiva nesses dispositivos. A seguir, propôs-se um novo sistema, em que a heterojunção constitui na mistura ternária polímero/CdSe/PCBM. Esses dispositivos foram caracterizados por curvas de corrente-potencial e pela resposta espectral do sistema, mostrando resultados extremamente promissores. Os sistemas ternários foram então investigados por diversas técnicas, como absorção, emissão, DRX, VC, TEM e microscopia de força atômica, a fim de determinar a atuação de cada componente da mistura ternária quando aplicados nas células solares. Esses resultados são apresentados no Capítulo V. No Capítulo VI, novos polímeros condutores derivados do polifluoreno, contendo unidades funcionais como grupos piridina, ou compostos aromáticos do tipo "push-pull", foram sintetizados pelo método de Gilch. A estrutura desses polímeros foi desenhada visando sua aplicação nas células híbridas, combinandoos com as nanopartículas de CdSe previamente sintetizadas. Esses materiais foram caracterizados por ressonância magnética nuclear de hidrogênio, espectroscopia no Infravermelho com transformada de Fourier. cromatografia por permeação em gel, análises térmicas e medidas eletroquímicas e de fotofísica. No Capítulo VII, propôs-se a introdução de um corante orgânico comercial (Disperse Red 1), como terceiro componente em uma mistura de poli(fluorenilenovinileno) e PCBM, visando aumentar a absorção de luz pela camada ativa do dispositivo. Foi realizado um extenso estudo usando técnicas fotofísicas e eletroquímicas para investigar o efeito da adição do corante, bem como determinar quais os tipos de processos (transferência de elétrons ou energia) ocorrem no sistema ternário. Finalmente o Capítulo VIII contém as principais conclusões deste trabalho e perspectivas de continuação para esta linha de pesquisa.
Abstract: This PhD Thesis investigated the development and characterization of new materials aiming at the application in hybrid solar cells. In Chapter I, a general introduction on the working principles and state-of-the-art of the organic solar cells, properties of the conducting polymers and the inorganic nanoparticles are presented. Chpater II highlights the aims of this work. In Chapter III, new conducting polymers based on the combination of fluorene, thiophene and/or benzene units are investigated. The photophysical and electrochemical characteristics, and charge mobility, are discussed. The polymers were also combined with a soluble fullerene derivative (PCBM) and these composites were used as active layer in bulk-heterojunction solar cells with the following configuration: ITO | PEDOT:PSS | Heterojunction | LiF | Al. Then, CdSe nanoparticles with different sizes were synthesized using a well-established method, and characterized using absorption and emission measurements, cyclic voltammetry (CV), X-ray diffraction (XRD) and transmission electron microscopy (TEM), as presented in Chapter IV. The previously characterized polymers were combined with the CdSe nanoparticles, and the nanocomposites were used to assemble hybrid solar cells. The devices showed very low photocurrent values, which were attributed to a poor electronic transport in the nanoparticles phase. Thus, a new system was suggested, based on a mixture of polymer/CdSe/PCBM. The photocurrent-potential curves and spectral response of the devices assembled with the ternary systems were evaluated, leading to very promising results. The absorption, emission, XRD, CV, TEM and atomic force microscopy measurements of the films were also performed to investigate/elucidate the role of each component in the ternary systems, as discussed in Chapter V. In Chapter VI, new conducting polymers based on poly(fluorenylenevinylene) containing functional units, such as pyridine or push-pull type aromatic units, were synthesized via the Gilch route. The structures of these materials were designed aiming at their application in hybrid solar cells, in combination with the previously synthesized CdSe nanoparticles. The polymers were characterized by magnetic nuclear resonance, Fourier transform infrared spectroscopy, gel permeation chromatography, and thermal, electrochemical and photophysical measurements. These polymers were combined with CdSe and/or PCBM and used as active layer in solar cells. In Chapter VII the addition of the commercial organic dye Disperse Red 1 in the mixture of poly(fluorenylenevinylene)/PCBM to enhance the light absorption in the active layer was investigated. A systematic study using photophysical and electrochemical measurements was performed in order to elucidate the effect of the dye addition, as well as the energy or electron transfer processes in this new ternary system. Finally, Chapter VIII summarizes the main conclusions of this work and highlights some perspectives for this exciting research filed.
Doutorado
Quimica Inorganica
Doutor em Ciências

Abstract This thesis presents a novel method for fabricating quantum dot light-emitting devices (QDLEDs) based on colloidal inorganic light-emitting nanoparticles incorporated into an organic semiconductor matrix. CdSe core/ZnS shell nanoparticles were inkjet-printed in air and sandwiched between organic hole and electron transport layers to produce efficient photon-emissive media. The light-emitting devices fabricated here were tested as individual devices and integrated into a display setting, thus endorsing the capability of this method as a manufacturing approach for full-colour high-definition displays. By choosing inkjet printing as a deposition method for quantum dots, several problems currently inevitable with alternative methods are addressed. First, inkjet printing promises simple patterning due to its drop-on-demand concept, thus overruling a need for complicated and laborious patterning methods. Secondly, manufacturing costs can be reduced significantly by introducing this prudent fabrication step for very expensive nanoparticles. Since there are no prior demonstrations of inkjet printing of electroluminescent quantum dot devices in the literature, this work dives into the basics of inkjet printing of low-viscosity, relatively highly volatile quantum dot inks: piezo driver requirements, jetting parameters, fluid dynamics in the cartridge and on the surface, nanoparticle assembly in a wet droplet and packing of dots on the surface are main concerns in the experimental part. Device performance is likewise discussed and plays an important role in this thesis. Several compositional QDLED structures are described. In addition, different pixel geometries are discussed. The last part of this dissertation deals with the principles of QDLED displays and their basic components: RGB pixels and organic thin-film transistor (OTFT) drivers. Work related to transistors is intertwined with QDLED work; ideas for surface treatments that enhance nanoparticle packing are carried over from self-assembled monolayer (SAM) studies in the OTFT field. Moreover, all the work done in this thesis project was consolidated by one method, atomic force microscopy (AFM), which is discussed throughout the entire thesis.

La cristallisation en continu de nanoparticules énergétiques est un défi de longue date. Le Spray Flash Evaporation (SFE) est une technique majeure développée et brevetée en interne, pour la production en continu de matériaux énergétiques submicroniques ou nanométriques ; la technologie se base sur la surchauffe d’un solvant pulvérisé dans le vide et s’évaporant de manière flash. Ce présent travail de recherche a pour but de comprendre et contrôler la cristallisation au sein du procédé SFE. Le RDX et le cocristal CL-20:HMX 2:1 sont étudiés. La sursaturation, concernant le SFE, est une fonction du temps et de l’espace liée aux tailles et vitesses de gouttes : elle fut variée par un anti-solvant et par l’amélioration du SFE avec un système double buse. Ensuite, PVP 40K et PEG 400 ont été utilisés afin de contrôler la nucléation et la croissance. Les particules ont pu être ajustées d’une taille de 160 nm à 5 µm, avec des morphologies facettées ou sphériques et avec des sensibilités moindres
The continuous formation of nanosized energetic material is a long-standing challenge. Spray Flash Evaporation (SFE) is a major technique, internally developed and patented, for continuously producing energetic materials at submicron or nano scale; it relies on the superheating of a solvent sprayed into vacuum and thus flashing. This present research project aims to understand and control the crystallisation occurring in the SFE process. RDX and the cocrystal CL-20:HMX 2:1 was studied overcome the limited in situ characterizations also. The supersaturation is a function of time and space in SFE, linked to the size distribution and velocity of droplets. Supersaturation was raised with an anti-solvent and by the enhancement of the SFE with a dual nozzle system. Then PVP 40K and PEG 400 were successfully used to alter the nucleation and the growth. The particles were subsequently tuned from 160 nm spheres to 5 µm grains and were less sensitive, especially toward electrostatic discharge

Atualmente com o advento da nanociência e nanotecnologia, as nanopartículas magnéticas têm encontrado inúmeras aplicações nos campos da biomedicina, diagnóstico, biologia molecular, bioquímica, catálise, etc. As nanopartículas magnéticas funcionalizadas são constituídas de um núcleo magnético, envolvido por uma camada polimérica com sítios ativos, que podem ancorar metais ou compostos orgânicos seletivos. Estas nanopartículas são consideradas materiais híbridos orgânico-inorgânicos de grande interesse em aplicações comerciais devido à particularidade das propriedades obtidas. Entre as aplicações importantes podemos citar: tratamento por magnetohipertermia, carregadores de fármacos para áreas específicas do corpo, seleção de moléculas específicas, biossensores, melhoria da qualidade de imagens por RMN, etc. O trabalho foi desenvolvido em duas partes: 1) a síntese do núcleo constituído de nanopartículas superparamagnéticas de ferrita de cobalto e, 2) o recobrimento do núcleo por um polímero bifuncional o 3-aminopropiltrietoxissilano. Os parâmetros estudados na primeira parte da pesquisa foram: pH, concentração molar da base, tipo de base, ordem de adição dos reagentes, modo de adição dos reagentes, velocidade de agitação, concentração inicial dos metais, fração molar de cobalto e tratamento térmico. Na segunda parte estudou-se: o pH, a temperatura, o catalisador, a concentração do catalisador, o tempo de reação, a relação H2O/silano, o tipo de meio, o agente umectante e a eficiência do recobrimento em relação ao pH. Os produtos obtidos foram caracterizados pelas técnicas de difratometria de raios-X (DRX), microscopia eletrônica de transmissão (MET), microscopia eletrônica de varredura (MEV), espectroscopia de energia dispersiva (EDS), espectroscopia de emissão atômica (ICP-AES), espectroscopia por infravermelho (FTIR), análises termogravimétricas (TGA/DTGA), calorimetria exploratória diferencial (DSC) e curvas de magnetização (MAV)
Nowadays with the appear of nanoscience and nanotechnology, magnetic nanoparticles have been finding a variety of applications in the fields of biomedicine, diagnosis, molecular biology, biochemistry, catalysis, etc. The magnetic functionalized nanoparticles are constituted of a magnetic nucleus, involved by a polymeric layer with active sites, which ones could anchor metals or selective organic compounds. These nanoparticles are considered organic-inorganic hybrid materials and have great interest as materials for commercial applications due to the specific properties. Among the important applications it can be mentioned: magnetohyperthermia treatment, drugs delivery in specific local of the body, molecular recognition, biossensors, enhancement of nuclear magnetic ressonance images quality, etc. This work was developed in two parts: 1) the synthesis of the nucleus composed by superparamagnetic nanoparticles of cobalt ferrite and, 2) the recovering of nucleus by a polymeric bifunctional 3-aminepropyltriethoxysilane. The parameters studied in the first part of the research were: pH, hydroxide molar concentration, hydroxide type, reagent order of addition, reagent way of addition, speed of shake, metals initial concentrations, molar fraction of cobalt and thermal treatment. In the second part it was studied: pH, temperature, catalyst type, catalyst concentration, time of reaction, relation ratios of H2O/silane, type of medium and the efficiency of the recovering regarding to pH. The products obtained were characterized using the following techniques X-ray powder diffraction (DRX), transmission electronic microscopy (MET), scanning electronic microscopy (MEV), spectroscopy of scatterbrained energy spectroscopy (DES), atomic emission spectroscopy (ICP-AES), themogravimetric analysis (TGA/DTGA), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and magnetization curves (VSM)

Des matériaux hybrides organiques/inorganiques formés de nanoparticules de TiO₂ et d’un polymère ont été synthétisés. Une copolymérisation de monomères hydrophobes (EMA) ethydrophiles (HEMA) a permis d’améliorer la stabilité des solutions hybrides en présence d’humidité, notamment sous atmosphère ambiante, tout en préservant, pendant au moins une semaine, la morphologie des nanoparticules jusqu’à des concentrations en titane de 3 mol/l. Les modifications de la composition des hybrides ont été investiguées pendant les étapes d’échange du solvant et de polymérisation. Il a été montré que les nanoparticules retiennent sur leur surface des molécules du solvant (2-propanol) même à haute température au-dessus du point d’ébullition(et jusqu’au point de décomposition). Les produits de décomposition les plus importants du HEMA ont été identifiés : 2-methyl propionic acid, 2-hydroxy ethyl acetate et methylmethacrylate. Ce dernier a été également observé comme une impureté de la synthèse. Les quantités des produits libérés son proportionnelles à la concentration des nanoparticules. Des analyses MET ont mis en évidence une distribution très homogène des nanoparticules d’une taille de 3,0 nm préalablement attribuée au nucleus servant de brique élémentaire dans la formation des solides de TiO₂. Ces résultats doivent être pris en compte lors des études de propriétés électroniques et fonctionnelles des matériaux afin d’envisager leurs champs d’application. Nous avons évalué ces matériaux hybrides inorganiques-organiques pour le micro-usinage laser par un procédé d’écriture direct par laser à deux photons
TiO₂-based nanoparticulate organic-iniorganic hybrid materials with the organic component consisting of co-polymers were prepared. A successful association of hydrophobic and hydrophilic organics makes the hybrid solutions stable against atmospheric moisture and preserved single nanoparticle morphology at high inorganics concentrations up to 3 mol/l Ti over a week. The compositional modifications of the hybrids were investigated at the solvent exchange and polymerization stages of preparation. It was shown that the inorganic nanoparticles retain solvent molecules at the surface even at high temperatures above boiling point (up to the organics decomposition temperature). The nanoparticles also catalyze the organics decomposition shifting this process to lower temperatures. The major products of HEMAisopropanol decomposition were assigned to 2-methyl propionic acid and 2-hydroxy ethyl acetate and methyl methacrylate, which last was also observed as the synthesis impurity. The quantities of the released species were proportional to the nanoparticles concentration. The TEM measurements evidenced unprecedently homogenous distribution of the smallest nanoparticles of the size 3.0 nm previously assigned to nucleus, which serves as elementary building block of TiO₂ solids. These findings have to be taken into consideration by investigating electronic properties of the materials and determining their application fields. We evaluated availability of the obtained nanoparticulate organic-inorganic hybrid materials for micromashining via DLW (2PP) processing

Actuellement, l'élaboration de matériaux nanohybrides organiques/inorganiques suscite l'engouement de nombreux chercheurs du fait de leurs diverses applications potentielles. Le but de ce projet de thèse a été de préparer et caractériser de nouveaux éléments inorganiques et organiques permettant la conception de nanohybrides multi-fonctionnels possédant des propriétés répondant aux problématiques actuelles. Dans cet objectif, nous avons préparé des nanoparticules d'oxyde de zinc (ZnO) en tant que composant inorganique par ablation laser. La surface de ces NPs peut être modifiée par des composés organiques possédant un groupe d'ancrage acide carboxylique. Nous avonssynthétisé et caractérisé des dérivés viologènes, bien connu comme de forts accepteurs d'électron, possédant le groupe d'ancrage. Les nanohybrides de ZnO/viologènes ont été préparés et caractérisés par diverses techniques de spectroscopie. Nous avons développé des voies de synthèse efficaces permettant d'obtenir une série de nouveaux hétérocycles possédant des propriétés de donneur d'électron : dérivés de dibenzo[2,3:5,6]pyrrolizino[1,7-bc]indolo[1,2,3-lm]carbazole. Ces nouvelles molécules présentent une forte stabilité thermique et une forte fluorescence dans le domaine du visible. Leurs propriétés d'absorption à un et deux photons (Proche-infrarouge) ainsi que leur habilité de donneur d'électron ont été étudiés expérimentalement et à l'aide de calculs de mécanique quantique. Les éléments organiques et inorganiques étudiés sont des motifs de choix pour l'élaboration future de nanohybrides utilisables pour diverses applications comme dans le domaine de l'énergie photovoltaïque ou encore l'imagerie médicale
Currently, the development of organic/inorganic nanohybrid materials arouses the enthusiasm of many researchers owing to their potential applications. The aim of this thesis was to prepare and characterize new inorganic and organic components for the future design of new multi-functional nanohybrids with properties responding to the current challenges. For this purpose, we have prepared nanoparticles of zinc oxide (ZnO) as the inorganic component by laser ablation. The surface of these nanoparticles can be modified by an organic component bearing the carboxylic group as an anchor. We synthesized and characterized a number of viologen derivatives, well known as strong electron acceptors, involving the anchoring groups. The nanohybrids of ZnO/viologens were prepared and characterized by various spectroscopic techniques. We have developed efficient synthetic routes toward a series of new heterocycles possessing the electron donating properties: derivatives of dibenzo[2,3:5,6]pyrrolizino[1,7-bc]indolo[1,2,3-lm]carbazole. These new molecules exhibit high thermal stability and strong fluorescence in the visible range. Their one- and two-photon (Near-infrared) absorption properties and electron donor ability were investigated experimentally and by means of quantum mechanical calculations. The studied organic and inorganic components can serve as promising building blocks of choice for the future development of nanohybrids used in various application domains such as in the fields of photovoltaics and medical imaging

Tesis por compendio
[ES] La presente tesis doctoral se centra en el diseño, síntesis y caracterización de varios nanodispositivos híbridos orgánico-inorgánicos, utilizando como soporte nanopartículas de sílice mesoporosa equipadas con enzimas y puertas moleculares, los cuales muestran capacidades comunicativas además de la evaluación de diferentes estrategias de comunicación. El primer capítulo incluye un resumen de diferentes conceptos sobre los que se fundamentan los estudios realizados tales como nanotecnología, materiales de sílice mesoporosa, materiales con puertas moleculares que reaccionan a estímulos específicos, partículas Janus y biocomputación. Finalmente, se incluyen conceptos básicos acerca de la comunicación química, materiales y estrategias empleados hasta ahora y ejemplos representativos. A continuación, en el segundo capítulo, se presentan los objetivos generales de esta tesis doctoral que son abordados en los siguientes capítulos experimentales. El tercer capítulo muestra un sistema de biocomputación para liberación basado en nanopartículas Janus de oro-sílice mesoporosa capaces de comunicarse con el entorno procesando la información e imitando la función lógica booleana propia de un demultiplexer y que resulta en la liberación controlada de la carga. Se muestra que dicho nanodispositivo puede llevar a cabo sus funciones en medios complejos como en células cancerígenas. En el cuarto capítulo, se presenta un modelo circular de comunicación dentro de una red de tres nanopartículas diferentes basado en el intercambio jerárquicamente programado de mensajes químicos. La parte mesoporosa del nanodispositivo 1 (S1βgal) es cargada con la especie fluorescente [Ru(bpy)3]Cl2 y tapada con cadenas de oligo(etilenglicol) que contienen puentes disulfuro y que funcionan como puertas moleculares, mientras que la enzima β-galactosidasa es unida a la parte del oro. En la nanopartícula 2 (S2galox), la enzima galactosa oxidasa es inmovilizada en la cara del oro mientras que la sílice mesoporosa es cargada con 4-(bromometil)benzoato de metilo y los poros tapados con un derivado de arilboronato autoinmolante sensible a H2O2 que forma un complejo huéspedanfitrión con β-ciclodextrina. Finalmente, el nanodispositivo 3 (S3est) es funcionalizado con la enzima esterasa en la parte del oro, cargada con la especie reductora hidroclururo de tris(2-carboxietil)fosfina (TCEP) en la parte mesoporosa y tapada con una nanoválvula supramolecular que responde a pH (βciclodextrina:benzimidazol). En el quinto capítulo, se muestra un modelo interactivo de comunicación química entre una nanopartícula Janus abiótica y un organismo vivo (Saccharomyces cerevisiae). En particular, el nanodispositivo está basado en nanopartículas funcionalizadas con glucosa oxidasa en la parte del oro, cargadas con el genotóxico fleomicina y tapadas con la puerta molecular sensible a pH (βciclodextrina:benzimidazol). El microorganismo usado en el estudio es una levadura modificada que expresa GFP bajo el control del promotor del gen RNR3; la transcripción de dicho gen es inducida con la exposición a agentes que dañan el ADN. La ruta de comunicación interactiva empieza con la adición de sacarosa (estímulo de entrada) la cual es hidrolizada en glucosa por la invertasa localizada en el espacio periplásmico de las levaduras y que difunde al nanodispositivo donde es trasformada en el correspondiente ácido por la glucosa oxidasa de la parte del oro. La bajada local de pH da lugar a la apertura de la nanoválvula sensible a pH del nanovehículo y con ello a la liberación de fleomicina (mensaje de vuelta) que induce la expresión de GFP (señal de salida) en las levaduras. En el sexto capítulo, proponemos una estrategia para establecer una comunicación lineal entre dos microorganismos diferentes que no interactúan entre ellos mediada por un nanodispositivo que actúa como traductor químico. Finalmente, las conclusiones generales de la presente tesis doctoral son expuestas en el capítulo siete. El estudio de las capacidades comunicativas de los nanodispositivos mesoporosos funcionalizados con enzimas permite la construcción de estrategias de cooperación entre diferentes entidades que permiten funcionalidades que van más allá que aquellas llevadas a cabo por agentes individuales.
[CA] La present tesi doctoral es centra en el disseny, síntesi i caracterització de diversos nanodispositius híbrids orgànic-inorgànics, utilitzant com a suport nanopartícules de sílice mesoporosa equipades amb enzims i portes moleculars, i que mostren capacitats comunicatives a més de l’avaluació de diferents estratègies de comunicació. El primer capítol inclou un resum de diferents conceptes sobre els quals es fonamenten els estudis realitzats com ara nanotecnologia, materials de sílice mesoporosa, materials amb portes moleculars que reaccionen a estímuls específics, partícules Janus i biocomputació. Finalment, s’inclouen conceptes bàsics sobre la comunicació química, materials i estratègies utilitzades fins ara i exemples representatius. A continuació, en el segon capítol, es presenten els objectius generals d’aquesta tesi doctoral que són abordats en els següents capítols experimentals. El tercer capítol mostra un sistema de biocomputació per alliberament basat en nanopartícules Janus d’or-sílice mesoporosa capaços de comunicar-se amb l’entorn processant la informació i imitant la funció lògica booleana pròpia d’un demultiplexer i que resulta en l’alliberament controlat de la càrrega. Es mostra que aquest nanodispositiu pot dur a terme les seves funcions en mitjans complexos com en cèl·lules canceroses. En el quart capítol, es presenta un model circular de comunicació dins d’una xarxa de tres nanopartícules diferents basat en l’intercanvi jeràrquicament programat de missatges químics. La part mesoporosa del nanodispositiu 1 (S1βgal) es carrega amb l’espècie fluorescent [Ru(bpy)3]Cl2 i es tapa amb cadenes d’oligo(etilenglicol) que contenen ponts disulfur i que funcionen com portes moleculars, mentre que l’enzim β-galactosidasa s’immobilitza a la part de l’or. A la nanopartícula 2 (S2galox), l’enzim galactosa oxidasa s’immobilitza a la cara de l’or mentre que la sílice mesoporosa es carrega amb 4-(bromometil)benzoat de metil i els porus són tapats amb un derivat d’arilboronat autoimmolant sensible a H2O2 que forma un complex hoste-amfitrió amb β-ciclodextrina. Finalment, el nanodispositu 3 (S3est) es funcionalitza amb l’enzim esterasa en la part de l’or, es carrega amb l’espècie reductora hidroclurur de tris (2-carboxietil) fosfina (TCEP) a la part mesoporosa i es tapa amb una nanoválvula supramolecular que respon a pH (β-ciclodextrina:benzimidazol). En el cinqué capítol, es mostra un model interactiu de comunicació química entre una nanopartícula Janus abiòtica i un organisme viu (Saccharomyces cerevisiae). En particular, el nanodispositiu està basat en nanopartícules funcionalitzades amb glucosa oxidasa en la part de l’or, carregades amb el genotòxic fleomicina i tapades amb la porta molecular sensible a pH (βciclodextrina:benzimidazol). El microorganisme utilitzat en l’estudi és un rent modificat que expressa GFP sota el control del promotor del gen RNR3; la transcripció d’aquest gen és induïda amb l’exposició a agents que danyen l’ADN. La ruta de comunicació interactiva comença amb l’addició de sacarosa (estímul d’entrada) la qual és hidrolitzada en glucosa per la invertasa localitzada en l’espai periplasmàtic dels rents i que difon al nanodispositiu on és transformada en el corresponent àcid per la glucosa oxidasa de la part de l’or. La baixada local de pH dona lloc a l’obertura de la nanoválvula sensible a pH del nanovehicle i amb això l’alliberament de fleomicina (missatge de tornada) que indueix l’expressió de GFP (senyal de sortida) en el rent. En el sisé capítol, proposem una estratègia per establir una comunicació lineal entre dos microorganismes diferents que no interactuen entre ells facilitada per un nanodispositiu que actua com a traductor químic. Finalment, les conclusions generals de la present tesi doctoral són exposades en el capítol set. L’estudi de les capacitats comunicatives dels nanodispositius mesoporosos funcionalitzats amb enzims permet la construcció d’estratègies de cooperació entre diferents entitats que permeten funcionalitats que van més enllà que aquelles dutes a terme per agents individuals. Esperem que els resultats obtinguts inspiren aplicacions futures en diferents àrees com ara biomedicina, nanorobots, materials que imiten la naturalesa i tecnologies de la informació.
[EN] This PhD Thesis is focused on the design, synthesis and characterization of several hybrid organic-inorganic nanodevices using mesoporous silica nanoparticles equipped with enzymes and molecular gates which display communication capabilities as well as the design and evaluation of different communication strategies. The first chapter includes an overview of the different concepts which lay the foundations of the presented studies such as nanotechnology, mesoporous silica materials, stimuli-responsive gated materials, Janus particles and biocomputing. Basic concepts of chemical communication, materials and enabling technologies employed so far and representative examples in this field are also included. Next, in the second chapter, the general objectives of this PhD Thesis that are addressed in the following experimental chapters are presented. The third chapter shows a biocomputing delivery system based on Janus gold-mesoporous silica nanoparticles capable of chemically communicating with the environment and processing the information mimicking a demultiplexer Boolean logic function which results in a programmed cargo release. Finally, it is shown that such nanodevice is operative in complex media such as cancer cells. In the fourth chapter, it is presented a circular model of communication within a network of three different nanoparticles based on the hierarchically programmed exchange of chemical messages. The mesoporous face of nanodevice 1 (S1βgal) is loaded with the fluorescent dye [Ru(bpy)3]Cl2 and capped with disulfidecontaining oligo(ethylene glycol) chains acting as gatekeepers, whereas the enzyme β-galactosidase is attached to the gold face. In nanoparticle 2 (S2galox), the enzyme galactose oxidase is immobilized on the Au face, while the mesoporous silica is loaded with methyl 4-(bromomethyl)benzoate and the mesopores capped with a H2O2-sensitive self-immolative arylboronate derivative which forms a host-guest complex with β-cyclodextrin. Finally, the nanodevice 3 (S3est) is functionalized with the enzyme esterase on the Au face, loaded with the reductive species tris(2- carboxyethyl)phosphine hydrochloride (TCEP) in the mesoporous face and capped with a pH-responsive supramolecular nanovalve (β-cyclodextrin:benzimidazole). In the fifth chapter, it is showed an interactive model of chemical communication between an abiotic Janus nanoparticle and a living organism (Saccharomyces cerevisiae). In particular, the nanodevice is based on Janus goldmesoporous silica nanoparticles functionalized with glucose oxidase on the Au face, loaded with the genotoxin phleomycin and capped with a pH-responsive (βcyclodextrin:benzimidazole) gatekeeper. The microorganism used in the studies is an engineered budding yeast that expresses GFP under the control of the RNR3 promoter; RNR3 gene transcription is induced upon exposure to DNA-damaging agents. The interactive communication pathway starts with the addition of sucrose (input) which is hydrolyzed into glucose by invertase located in periplasmic space of yeasts and diffuses to the nanodevice where it is transformed into the corresponding acid by glucose oxidase on the Au face. The local drop in pH leads to uncapping of the pH-sensitive nanovalve in the nanocarrier and the release of phleomycin (feedback messenger) that induces GFP expression (output) in yeasts. In the sixth chapter, we propose a strategy to establish linear communication between two different non-interacting microorganisms mediated by a nanodevice which acts as a chemical “nanotranslator”. Finally, the general conclusions from this PhD Thesis are presented in chapter seven. The study of communication capabilities of enzyme-functionalized mesoporous nanodevices enables the construction of strategies of cooperation between different entities allowing sophisticated functionalities that go beyond those carried out by individual agents. We hope that the obtained results inspire future applications in different areas such as biomedicine, nanorobots, life-like materials and information technologies.
The authors wish to thank the Spanish Government (projects RTI2018-100910-B-C41 and RTI2018-101599-B-C22 (MCUI/AEI/FEDER, UE), CTQ2017-87954-P), the Generalitat Valenciana (PROMETEO 2018/024), the Comunidad de Madrid (IND2017/BMD7642) and CIBER-BBN (NANOCOMMUNITY project) for support.
De Luis Fernández, B. (2021). Development of enzyme-functionalized hybrid mesoporous nanodevices for advanced chemical communication [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/171506
TESIS
Compendio

[EN] Abstract The present PhD thesis entitled "Supramolecular Chemistry: New chemodosimeters and hybrid materials for the chromo-fluorogenic detection of anions and neutral molecules" is based on the application of supramolecular chemistry and material science principles for the development of optical chemosensors for anions and neutral molecules detection. The second chapter of this PhD thesis is devoted to the preparation of chemodosimeters for the chromo-fluorogenic detection of fluoride, diisopropyl fluorophosphates (DFP) and hydrogen sulfide. The optical detection of fluoride anion was achieved by using a pyridine derivative containing a t-butyldimethylsilyl ether group. Aqueous solutions of the chemodosimeter were colorless but turned yellow upon addition of fluoride anion. Also a remarkable enhancement in emission was observed only upon the addition of fluoride. The optical changes were ascribed to a fluoride-induced hydrolysis of the silyl ether moiety. Also a chemodosimeter for the optical recognition of DFP, a nerve agent simulant, was prepared. In this case, the chemodosimeter was based on a stilbene pyridinium derivative functionalized with hydroxyl and silyl ether moieties. Aqueous solutions of the chemodosimeter were colorless changing to yellow upon DFP addition. The optical changes were ascribed to a hydroxyl phosphorylation followed by a fluoride-induced hydrolysis of the silyl ether group. Besides, that probe was implemented in test strips and DFP detection in gas phase was accomplished. Finally, the fluorogenic recognition of hydrogen sulfide anion was explored. For this purpose different fluorophores were selected and fucntionalized with 2,4-dinitrophenyl ether groups. The prepared probes were neraly non-emissive but remarkable emission enhancements upon addition of hydrogen sulfide were observed. The emission enhancements observed were due to a selective sulfide-induced hydrolysis of the 2,4-dinitrophenyl ether moiety that yielded the free fluorophores. Another set of chemodosimeters equipped with azide and sulfonylazide moieties were prepared. Again these probes were non-fluorescent but upon addition of hydrogen sulfide an important enhancement in emission was found. The selective response was ascribed to a reduction of the azide and sulfonylazide moieties to amine and sulfonylamide induced by hydrogen sulfide anion. Besides, the viability assays showed that these dosimeters were essentially non-toxic and real-time fluorescence imaging measurements confirmed their ability to detect intracellular hydrogen sulfide at micromolar concentrations. The third chapter of this PhD thesis was devoted to the preparation of nanoscopic gated materials and their use in sensing protocols. In a first step a gated material for the optical detection of glutathione (GSH) was prepared. For this purpose MCM-41 mesoporous silca nanoparticles were selected as inorganic scaffold. The pores were loaded with safranine O and the external surface was functionalized with disulfide-containing oligo(ethylene glycol) moieties. Dye delivery from aqueous suspensions of the sensory material was only observed in the presence of GSH. The signalling paradigm was ascribed to the selective reduction of the disulfide bond by GSH which induced pore opening and dye release. Also capped organic-inorganic hybrid materials for the selective detection of hydrogen sulfide were prepared and characterized. In this case the same MCM-41 support was used and charged with [Ru(bipy)3]2+ dye. Then, the external surface was functionalized with Cu(II)-macorcyclic complexes and finally, the pores were capped by the addition of the bulky anion hexametaphosphate. Aqueous suspensions of this material showed negligible dye release whereas in the presence of hydrogen sulfide anion a remarkable colour change was observed. This optical response was ascribed to a demetallation process of the Cu(II) complex induced by hydrogen sulfide.
[ES] Resumen La presente tesis doctoral titulada "Química supramolecular: Nuevos dosímetros químicos y materiales híbridos para la detección cromo-fluorogénica de aniones y moléculas neutras." está basada en la aplicación de principios básicos de la química supramolecular y de la ciencia de materiales en el desarrollo de sensores ópticos para aniones y moléculas neutras. El segundo capítulo de esta tesis doctoral está dedicado a la preparación de dosímetros químicos para la detección cromo-fluorogénica de fluoruro, diisopropil fluorofosfato (DFP) y sulfuro de hidrógeno. Para la detección óptica del anión fluoruro se sintetizó un derivado de piridina funcionalizado con un t-butildimetilsilil éter. En este capítulo también se describe la preparación de un dosímetro químico para la detección de DFP, que es un simulante de agentes nerviosos. Este dosímetro está basado en un estilbeno funcionalizado con una sal de piridinio que contiene grupos hidroxilo y silil éter en su estructura. Finalmente se prepararon dos familias de sensores para la detección óptica de hidrógeno sulfuro. La primera familia de sensores consiste en fluoróforos comunes funcionalizados con 2,4-dinitrofenil éteres. Los sensores preparados no presentaron una emisión de fluorescencia importante mientras que, en presencia del anión hidrógeno sulfuro, se observó un aumento significativo. La segunda familia de dosímetros también estaba compuesta por ciertos fluorofóros pero, en este caso, funcionalizados con grupos azida y sulfonilazida. Los dosimétros preparados, siguiendo esta segunda aproximación, tampoco dieron una fluorescencia significativa observándose un aumento de la misma al añadir el anión hidrógeno sulfuro. El tercer capítulo de esta tesis doctoral está dedicado a la preparación de materiales híbridos nanoscópicos funcionalizados con puertas moleculares y su aplicación en protocolos de reconocimiento. En primer lugar se preparó un material para la detección óptica de glutatión (GSH). Para ello se emplearon nanopartículas de MCM-41 mesoporosas como soporte inorgánico. Los poros del soporte fueron cargados con el colorante safranina O y la superficie externa funcionalizada con oligo(etilenglicol) conteniendo enlaces disulfuro. También se prepararon y caracterizaron varios materiales híbridos para la detección selectiva del anión hidrógeno sulfuro. En este caso también se empleó, como soporte inorgánico, sílice mesoporosa MCM-41. Los poros del soporte inorgánico fueron cargados con [Ru(bipy)3]2+ y la superficie externa funcionalizada con varios complejos macrocíclicos de Cu(II). El material sensor final fue obtenido al añadir el anion hexametafosfato, que compleja con los complejos de Cu(II), produciendo un bloqueo de los poros.
[CAT] Resum La present tesi doctoral titulada "Química supramolecular: Nous dosímetres químics i materials híbrids per a la detecció cromo-fluorogènica d'anions i molècules neutres." està basada en l'aplicació dels principis bàsics de la química supramolecular i de la ciència dels materials en el desenvolupament de sensors òptics per a anions i molècules neutres. El segon capítol d'aquesta tesi doctoral està dedicat a la preparació de dosímetres químics per a la detecció cromo-fluorogènica de fluorur, diisopropil fluorofosfat (DFP) i sulfur d'hidrogen. Per a la detecció òptica de l'anió fluorur es va sintetitzar un derivat de piridina funcionalitzat amb un t-dibutildimetilsilil èter. En aquest capítol també es descriu la preparació d'un dosímetre químic per a la detecció de DFP, que és un simulant d'agents nerviosos. Aquest dosímetre està basat en un estilbè funcionalitzat amb una sal de piridina que conté grups hidroxil i silis èter en la seua estructura. Finalment varen ser preparades dues famílies de sensors per a la detecció òptica de sulfur d'hidrogen. La primera família consisteix en fluoròfors comuns funcionalitzats amb 2,4-dinitrofenil èters. Els sensors preparats no presentaren una emissió de fluorescència significativa mentre que, en presencia de l'anió hidrogen sulfur, es va observar un augment significatiu. La segona família de dosímetres també estava composada per certs fluròfors però, en aquest cas, funcionalitzats amb grups azida i sulfonilazida. Els dosímetres preparats, seguint aquesta segona aproximació, tampoc donaren una fluorescència significativa observant-se un augment de la mateixa al afegir l'anió hidrogen sulfur. El tercer capítol d'aquesta tesi doctoral està dedicat a la preparació de materials híbrids nanoscòpics funcionalitzats amb portes moleculars i la seua aplicació en protocols de reconeixement. En primer lloc es va preparar un material per a la detecció òptica de glutatió (GSH). Per a aquest propòsit es varen emprar nanopartícules MCM-41 mesoporoses com a suport inorgànic. Els porus del suport varen ser carregats amb el colorant safranina O i la superfície externa funcionalitzada amb oligo(etilenglicol) que contenia enllaços disulfurs. També varen ser preparats i caracteritzats diversos materials híbrids per a la detecció selectiva de l'anió hidrogen sulfur. En aquest cas també es va emprar, com a suport inorgànic, sílice mesoporosa MCM-41. Els porus del suport inorgànic varen ser carregats amb [Ru(bipy)3]2+ i la superfície externa funcionalitzada amb diversos complexos macrocíclics de Cu(II). El material sensor final es va obtindre al afegir l'anió hexametafosfat, que es complexa amb macrocicles de Cu(II), produint un bloqueig dels porus.
El Sayed Shehata Nasr, S. (2015). Supramolecular Chemistry: New chemodosimeters and hybrid materials for the chromo-fluorogenic detection of anions and neutral molecules [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/52598
TESIS

Chemically functionalized alumina nanoparticles (carboxylate-alumoxanes) are used as the inorganic component of a new class of inorganic-organic material. Lysine- or para-hydroxybenzoic acid-derivatized alumoxanes are prepared from the reaction of boehmite, [Al(O)(OH)]n, with the appropriate carboxylic acid. The peripheral hydroxides and amines of these alumoxanes react directly with DER 332 epoxide to form a hybrid material, or in the presence of a resin and hardener system, to form a composite material. Solid state NMR spectroscopy demonstrates that the alumoxanes are chemically bound to the resin matrix. The properties and cure times of the alumoxane materials are distinct from both the pure resins and from a physical blend of the resins with traditional fillers. A significant increase in thermal stability and tensile strength is observed for the resin systems. In order to produce molecular coupling layers, epoxides cross-linked with self-assembled monolayers (SAMs) grown on the native oxide of aluminum thin films on silicon substrates have been investigated. Specifically, SAMs have been formed by the attachment of different carboxylic acids. In order to investigate the cross-linking reaction between carboxylate monolayers and an epoxide, grown monolayers were reacted with a mono-epoxy resin. In addition to these surface materials, aluminum oxide surfaces supporting carboxylate monolayers were reacted in pairs with DER 332 to form a structural adhesive. These materials have been characterized variously by SEM, AFM, XPS, EDX, and contact angle measurements. The particle size dependence on pH of a series of alumoxanes was investigated. For each of the alumoxanes, PCS particle size measurements were obtained as a function of pH. In all cases, particle size control was afforded by variations in pH. Finally, crystal structures of several model compounds were determined by X-ray crystallography, and shown to form either sheets of dimers or tetrameric units. Through a review of structures found in the Cambridge Crystallographic Database, compounds of the type X-CH(OH)CH 2NH-Y were investigated. The results of this study lead to a generalized approach for predicting the packing motifs of racemic mixtures in polar space groups.