Emociones y cine en alumnado con necesidades específicas de apoyo educativo

A través del siguiente trabajo se pretende explicar a los alumnos con necesidades específicas de apoyo educativo a expresar y comprender sus emociones. A partir de la película de Inside Out, se realizarán una serie de actividades de una manera lúdica y motivadora para el alumnado. No sólo se trabajara con la película, sino que se utilizarán todos los recursos de los cuales se dispone en el aula de Pedagogía Terapéutica, en este caso desde un centro de Educación Especial. Se utilizará una metodología activa, individualizada, integral y motivadora. Con las actividades planteadas se ha intentado que el alumno pueda comprender e interiorizar de una manera lúdica las cinco emociones básicas

Functional CdSe and CdSe/ZnS nanoparticles capped with thiols: photophysical and photochemical properties and applications as sensors

Esta tesis se centra en el efecto simbiótico entre los QDs de CdSe o CdSe/ZnS y sus ligandos orgánicos, y las ventajas de este efecto para mejorar la funcionalidad del QD y/o del ligando, o crear una nueva funcionalidad del sistema. Así : 1. la superficie de las nanopartícula recubierta con ligandos orgánicos puede permitir al QD i) permanecer estable en disolventes orgánicos o acuosos, debido a la repulsión estérica o iónica entre las nanopartículas, ii) mantener o aumentar sus propiedades emisivas (pasivación de los defectos de superficie, aumento de distancia entre nanopartícula y moléculas desactivadoras), y/o iii) para proporcionar funcionalidad a la nanopartícula. 2. la forma esférica de la nanopartícula favorece la localización de un elevado número de ligandos en la superficie del QD. Por lo tanto, es posible tener una alta concentración local de un grupo funcional en la periferia QD, incluso en solución diluidas. 3. la acción combinada del QD y el ligando puede permitir la encapsulación o interdigitalización de otras moléculas, acercándolas a la superficie del QD. Además, el ligando funcional puede modificar reversiblemente las propiedades emisivas de las nanopartículas y esto ser utilizado para la detección de analitos, entre otras aplicaciones. Existe una gran interés en la pasivación de los QDs de CdSe y CdSe/ZnS con ligandos orgánicos que poseen en uno de sus extremos un grupo mercapto debido a la alta afinidad de este grupo por la superficie del QD, principalmente cuando está como tiolato. Sin embargo, el intercambio de ligandos de los QDs (generalmente preparados con ligandos amino) por tiol (QDs tipo core ) o tiolatos (QDs tipo core-shell) produce una considerable reducción de las propiedades luminiscentes de ambos QDs. En el caso de los QDs tipo core, el tiol atrapa el hueco formado tras la excitación del QD, y por lo tanto evita la recombinación electrón-hueco. La baja emisión del QD tipo core-shell es atribuida a una alteración en la superficie del QD durante intercambio de ligando. Durante esta tesis, hemos desarrollado una nueva estrategia para obtener QDs de CdSe/ZnS pasivados con tiolatos, altamente fluorescentes, solubles en medios orgánicos y en agua, basada en la quimisorción de tioles en la superficie QD. En esta estrategia el ligando nativo amina del QD juega un papel clave, ya que ayuda a la disociación el tiol cerca de la superficie QD. La sustitución de las aminas de cadena larga por tioles se llevó a cabo bajo condiciones de reacción suaves, lo que permite preservar o incluso mejorar las propiedades luminiscentes de los QD. Esta metodología se llevo a cabo con éxito tanto en nanopartículas sintetizadas en el laboratorio como en aquellas disponibles comercialmente. Además, estos QDs mostraron mayor fotoestabilidad que los QDs funcionalizados con amina. Estos resultados son de gran interés para la fabricación de nuevos dispositivos para la detección o reconocimiento molecular, basado en procesos de transferencia de energía o de electrones. Así pues, esta estrategia fue utilizada para la preparación de QDs de CdSe/ZnS, altamente fluorescentes y soluble en agua, pasivados con un ligando bifuncional, con un grupo mercapto (grupo de anclaje) en un extremo y una benzofenona en el otro. Este QD se usó para desarrollar un sistema supramolecular, basado en una nanopartícula de CdSe/ZnS funcionalizada con ketoprofeno y una β-ciclodextrina modificada con una molécula de pireno. Las unidades de ketoprofeno favorecen el reconocimiento molecular entre la nanopartícula y la ciclodextrina y, al mismo tiempo, sitúan la unidad de pireno cerca a la superficie de nanopartículas, provocando la desactivación de la fluorescencia del QD. Este efecto simbiótico se utilizó con éxito para la detección molecular de diferentes analitos. El proceso de detección de este sistema híbrido, eficaz y fácil de preparar, se basa en la recuperación de la intensidad de fluorescencia del QD en respuesta a diferentes analitos. Además, la metodología diseñada permitió la recuperación individual de todos los componentes utilizados en este sistema, lo cual es muy deseable tanto desde el punto de visto económico como medioambiental. Como se mencionó anteriormente el QD puede ser utilizado como nano-transportador de un grupo funcional, lo que conduce a un aumento de la concentración local del grupo funcional en una solución diluida. En esta tesis, QDs de CdSe fueron utilizados como soportes de moléculas de pireno, y, como consecuencia, se observó la formación del excímero del pireno utilizando concentraciones muy bajas del ligando pireno. La luminiscencia de los QDs de CdSe se redujo drásticamente debido al uso de un ligando pireno que posee un grupo mercapto como grupo de anclaje. Este sistema fue utilizado para estudiar la influencia del QD en la fotoestabilidad del pireno en diferentes disolventes clorados y se compararon con los resultados obtenidos con pireno libre. Estos estudios demuestran que la combinación de cloroformo y la luz produce una alta fotodegradación de todos los sistemas de pireno, mientras que en diclorometano son altamente estables. Finalmente, se estudiaron sistemas híbridos QD-organogel, altamente fluorescentes, a partir de un macrociclo pseudopeptídico, y ambos tipos de QDs (CdSe y CdSe/ZnS pasivados con diferentes ligandos). Estos organogeles híbridos se prepararon fácilmente por calentamiento del organogelante en tolueno, seguido de la adición de los QDs y del posterior enfriamiento del sistema a temperatura ambiente. La presencia del QD en el sistema QD-organogel disminuye la concentración crítica del organogelante necesaria para formar los organogeles estables y termorreversibles, sin afectar significativamente el interior de la red fibrilar del organogel. Además, el efecto del organogelante en las propiedades luminiscentes de los QDs depende de la presencia de la capa de ZnS. Las propiedades fotofísicas de los QDs de CdSe/ZnS se mantuvieron en el medio organogel, mientras que en el caso de los QDs de CdSe se observó un importante aumento de la intensidad de fluorescencia. Demostramos que el macrociclo interactúa con los ligandos del QD de CdSe incluso antes de la gelificación, mediante el uso de metodologías usuales, tales como IR y RMN. Esta es la primera vez que se reporta la interacción entre un organogel y un QD.This thesis focuses on the symbiotic effect between CdSe/ZnS core-shell QDs or CdSe core QDs and their organic ligands, and the advantages of this effect to improve the functionality of the QD or/and of the ligand, or create a new functionality of the device. Thus, 1. the nanoparticle surface capping with organic ligands can allow the QD i) to remain stable in organic solvents or water, by providing steric or ionic repulsion between the nanoparticles, ii) to preserve/enhance their emissive properties (passivation of the surface defects, isolation from quenchers), and/or iii) to add functionality to the nanoparticle. 2. the spherical shape of the nanoparticle makes the location of an elevated number of ligands on the QD surface possible. Therefore, it is possible to have a high local concentration of a functional group at the QD periphery, in an otherwise diluted solution. 3. the combined action of the QD and the ligand can permit the encapsulation/interdigitation of other molecules, bringing them closer to the QD surface. In addition, the functional ligand can reversibly modify the nanoparticles emissive properties and this can be used, for example, for sensing applications. There is great interest on the passivation of CdSe core and CdSe/ZnS core-shell QDs with organic ligands possessing a mercapto group at one end, because of the high affinity of this anchoring group to the QD surface, mainly when it is as thiolate. Nevertheless, exchange of the ligands of the QDs (usually prepared with amino ligands) by thiol (core) or thiolates (core-shell) causes a remarkable reduction of the luminescent properties of both type of QDs. In the case of the core QDs, the thiol traps the hole of the excited QD, and therefore prevents the electron-hole recombination. The low emission of the core-shell QD has been attributed to the alteration of the QD shell during the ligand exchange. We have developed a new strategy to obtain highly fluorescent organic-soluble and water-soluble CdSe/ZnS QDs passivated with thiolates, based on the chemisorption of thiols on the QD surface. In this strategy the QD amine native ligand plays a key role, by dissociating the thiol in the vicinity to the QD surface. The replacement of the long chain amines by thiols was performed under mild conditions, and it allows preserve or even improve the QD luminescent properties. This methodology was tested in home-made and commercially available nanoparticles. Moreover, the QDs were more photostable than those capped with amine. These results are of interest for constructing new devices of application in sensing or molecular recognition, based on energy or electron transfer processes. Thus, that strategy was used in the preparation of highly fluorescent water-soluble CdSe/ZnS QDs capped with a bifunctional ligand, with a mercapto group (the anchoring group) at one end and a benzophenone moiety at the other. The QD was used to develop a supramolecular system, based on ketoprofen-functionalized CdSe/ZnS QDs and pyrene-modified cyclodextrin (CD). The ketoprofen units play a key role, ensuring the molecular recognition between the nanoparticle and the cyclodextrin and, at the same time, places the pyrene unit near to the nanoparticle surface, resulting in QD fluorescence quenching. This symbiotic effect was successfully used for molecular sensing of different analytes. The sensing of this easy-to-prepare and effective hybrid system is based in the recovery of the QD fluorescence intensity in response to different analytes. In addition of this, the methodology proposed allows the individual recovery of all the components used in the mentioned system, which is highly desirable both from the commercial and environmental points of view. As stated before, the QD can be used as nano-carrier of a functional group, leading to increase of the local concentration of the functional group in an otherwise diluted solution. In this thesis, CdSe QDs were used as carriers of pyrene moieties, and, as a consequence, making the formation of the pyrene excimer possible by using a very low concentration of the pyrene ligand. The CdSe QD luminescence was drastically reduced by using a pyrene ligand with mercapto group as the anchoring group. The system was used to study the influence of the QD on the photostability of the pyrene in chlorinated solvents and the results were compared to those of the free pyrene. These studies evidenced that the combination of chloroform and light produces a high photodegradation of all the pyrene systems, while they were highly stable in dichloromethane. Finally, we studied highly fluorescent QDs-organogels prepared from a pseudopeptidic macrocycle and both types of QDs, i.e. CdSe and CdSe/ZnS capped with different ligands. These hybrid organogels were easily prepared, by heating the organogelator in toluene, followed by the addition of the QDs and the cooling of the system to room temperature. The presence of the QD in the organogel system decreases the critical concentration of the gelator needed to form stable and thermoreversible organogels, without affecting significantly the internal fibrillar network of the organogel. In addition, the effect of the organogel on the luminescent properties of the QDs depends on the presence of the ZnS shell. The photophysical properties of CdSe/ZnS core-shell QDs are preserved in the organogel media, while in the case of CdSe core QDs, an enormous increase of the fluorescence intensity was observed. We demonstrate that the macrocycle interacts with the CdSe QD ligand even before gelation, by using common methodologies, such as IR and NMR spectroscopies. This is the first time that the interaction between an organogel and a QD has been reported

Synthesis and applications of metal-organic framework–quantum dot (QD@MOF) composites

The combination of the high surface areas, microporosity and tuneable compositions of metal-organic frameworks (MOFs) with the desirable photo-physical behaviour of semiconductor nanoparticles or quantum dots (QDs), allows the preparation of composite materials with enhanced properties for applications in photocatalysis, energy, gas-storage and sensing. These QD@MOF composites are an emergent class of materials and in this review we discuss current strategies for their synthesis, consider the semiconductor behaviour of MOFs themselves and present the applications of the various materials reported this far grouped by the nature of the QD component

Wavelength-Tunable Light-Induced Polymerization of Cyanoacrylates Using Photogenerated Amines

Cyanoacrylate photopolymerization has already been described, but it generally requires the use of organometallic photoinitiators and highly reactive monomers, which often leads to photoinitiator-monomer mixtures with limited stability. In this work we report a method to tackle these limitations, which relies on the use of amines bearing photoremovable protecting groups as light-responsive nucleophilic cyanoacrylate initiators. By exploiting the versatility of amine photorelease strategies, we have developed a series of all-organic initiators that (a) enable fast, on demand photocuring of commercial formulations of various cyanoacrylates, including less reactive, biologically relevant long alkyl chain monomers; (b) show wavelength tunability along the UV-vis spectrum and good thermal stability in the dark; and (c) lead to polymeric materials with excellent adhesive behavior. Because of this combination of properties, photogenerated amines appear as ideal candidates to bring cyanoacrylate photopolymerization into real application, especially in the biomedical field

Polymethylferrocene-induced photopolymerization of cyanoacrylates using visible and near-infrared light

Metallocene-induced photopolymerization of cyanoacrylates based on electron transfer processes has been proposed as an alternative to more conventional light-curing strategies relying on photobase generators. However, successful application of this methodology has so far only been achieved for very reactive cyanoacrylates under UV illumination and long irradiation times, which eventually hampers its practical use. To overcome these limitations, we describe in this work the use of electron-rich polymethylferrocenes as photoinitiators, with which fast light-induced polymerization of commercial formulations of less reactive, but more relevant long alkyl chain cyanoacrylates has been accomplished by illumination with visible and even near-infrared light. In addition, generalization of this technology to other electron-deficient, noncyanoacrylate monomers has been demonstrated. The low oxidation potential of polymethylferrocenes accounts for these excellent results, which strongly favors the formation of radical anions by electron transfer that initiate the polymerization reaction. Because of the high molecular weight and superior adhesive behavior of the resulting polymer materials as well as the facile access to polymethylferrocenes, they emerge as very attractive photoinitiators for the light-curing of cyanoacrylate (and other) glues in real applications

Halochromic coordination polymers based on a triarylmethane dye for reversible detection of acids

Chromeazurol B (Na2HL) is a pH-sensitive (halochromic) dye based on a hydroxytriarylmethane core and two carboxylate functional groups, which makes it suitable for the synthesis of coordination polymers. Two new coordination polymers [NaZn4(H2O)3(L)3]·3THF·3H2O (1) and [Zn3(H2O)3(μ2- OH2)(μ3-OH)(HL)2(H2L)]·2THF·3H2O (2) incorporating Chromeazurol B linkers have been prepared and characterised. The structure of 1 comprises pentanuclear heterometallic {Zn4Na} nodes linked by six L3– anions to give a layered structure with a honeycomb topology. 2 crystallizes as a double-chain ribbon (ladder) structure with two types of metal node: a mononuclear Zn(II) cation and tetranuclear {Zn(II)}4 cluster. Chromeazurol B anions link each tetranuclear cluster to four individual Zn(II) cations and each Zn(II) cation with four tetranuclear clusters. Both compounds show pH-sensitivity in water solution which can be observed visually, giving the first example of a halochromic coordination polymer. The halochromic properties of 1 towards HCl vapors were systematically investigated. As-synthesized violet-grey 1 reversibly changes color from orange to pink in the presence of vapors of 2M and 7M HCl, respectively. The coordination of the Chromeazurol B anion at each color stage was examined by diffuse reflectance spectroscopy and FT-IR measurements. The remarkable stability of 1 to acid and the observed reversible and reproducible color changes provide a new design for multifunctional sensor materials

Current trend in synthesis, Post-Synthetic modifications and biological applications of Nanometal-Organic frameworks (NMOFs)

Since the early reports of MOFs and their interesting properties, research involving these materials has grown wide in scope and applications. Various synthetic approaches have ensued in view of obtaining materials with optimised properties, the extensive scope of application spanning from energy, gas sorption, catalysis biological applications has meant exponentially evolved over the years. The far‐reaching synthetic and PSM approaches and porosity control possibilities have continued to serve as a motivation for research on these materials. With respect to the biological applications, MOFs have shown promise as good candidates in applications involving drug delivery, BioMOFs, sensing, imaging amongst others. Despite being a while away from successful entry into the market, observed results in sensing, drug delivery, and imaging put these materials on the spot light as candidates poised to usher in a revolution in biology. In this regard, this review article focuses current approaches in synthesis, post functionalization and biological applications of these materials with particular attention on drug delivery, imaging, sensing and BioMOFs

A colloidal water-stable MOF as a broad range fluorescent pH sensor via post-synthetic modification

We report for the first time the pH-dependent fluorescence of UiO-66-NH2 across the wide range from 1 to 9. By application of a post-synthetic modification (PSM) diazotisation strategy, we synthesized a new material, UiO-66-N=N-ind, which shows increased chemical stability and enhanced sensing up to pH 12

Surfactant-assisted ZnO processing as a versatile route to ZIF composites and hollow architectures with enhanced dye adsorption

Metal oxides can be used as hard sacrificial templates for the preparation of multifunctional core–shell MOF-based composites following reaction with an organic linker. This is a facile method, but often structures of well-defined shape are only obtained under narrow ranges of conditions, the shape can be lost completely and low levels of MOF conversion observed. Using the prototypical framework ZIF-8 we present an alternative surfactant-assisted surface passivation strategy where the ZnO precursor particles are first coated with a guanidinium-based amphiphile. The surfactant interacts strongly with the oxide surface and allows fine-tuning of the release of Zn(II) and ZIF-8 nucleation by the level of surface coverage permitting a range of well-defined ZnO@ZIF-8 core–shell architectures to be prepared including in water. Further, selective base-etching of the oxide core provides facile access to hollow ZIF-8 and yolk–shell structures. We also demonstrate enhanced dye adsorption and recovery from aqueous mixtures using ZnO@ZIF-8 composite microspher

Magnetic MOF microreactors for recyclable size-selective biocatalysis

In this contribution we report a synthetic strategy for the encapsulation of functional biomolecules within MOF-based microcapsules. We employ an agarose hydrogel droplet Pickering-stabilised by UiO-66 and magnetite nanoparticles as a template around which to deposit a hierarchically structured ZIF-8 shell. The resulting microcapsules are robust, highly microporous and readily attracted to a magnet, where the hydrogel core provides a facile means to encapsulate enzymes for recyclable size-selective biocatalysi