Baliabide molekularrak propieta fotoenikoen sintonizaziorako

258 p.(eng.) 144 p. (eusk.)La química de colorantes está presenciando un renovado reconocimiento como herramienta valiosa para diseñar materiales fotónicos inteligentes prácticos. Las recientes rutas sintéticas en química orgánica han permitido el acceso a nuevas estructuras moleculares, en particular las hechas a la medida. En este contexto, nuestro objetivo en esta tesis es diseñar, caracterizar y aplicar una nueva generación de colorantes orgánicos como fluoróforos y fotosensibilizadores con fines fotónicos. En lugar de usar diferentes colorantes para cada propósito de aplicación, la estrategia empleada aquí se basó en el uso de un punto de partida molecular específico, donde, tras adecuadas modificaciones químicas de su núcleo coromofórico, la función fotónica pudo ser modulada de una manera controlada dependiendo del campo de aplicación que se quería perseguir. Es por ello que se eligió el colorante BOro DIPYrrometeno (BODIPY) como patrón molecular para hacer frente a diferentes aplicaciones fotónicas, incluso cuando a veces implicaban propiedades fotofísicas opuestas. Un diseño lógico de su estructura molecular permite el desarrollo de colorantes capaces de emitir en la región roja e infrarroja cercana para ser aplicados como láseres sintonizables, sensores fluorescentes para la detección de biomoléculas, y pruebas fluorescentes para bioimagen, así como fotosensibilizadores no fluorescentes capaces de generar oxigeno singlete para terapia en biomedicina. Su diseño se amplió a través de la combinación de numerosos colorantes en una única estructura molecular, donde los nuevos fenómenos fotofísicos como la transferencia de energía y carga, y los acoplamientos excitónicos, son impulsados. Estos colorantes multicromofóricos complejos y desafiantes presentan un comportamiento excepcional como láseres de colorante mejorados, sistemas ópticamente activos, captadores de luz y antenas moleculares

Shifting Gears Towards the Red: Novel Boron-Based Fluorophores for Bioimaging Applications

Advancements in near-infrared (NIR) fluorescence imaging have enabled greater tissue penetration depths, high spatial resolution, reduced photon scattering, and minimal interference from tissue autofluorescence. Hence, NIR fluorophores exist as viable candidates for biological imaging applications, as well as providing unique insights into complex biological processes to better understand disease etiology. In this work, a series of novel boron-based coumarin and rhodamine-like fluorophores were developed and tested. Initially, modifications to the coumarin scaffold were investigated to develop more red-shifted dyes, whereby incorporation of a p-conjugated bridge was determined to be a critical component. Confocal microscopy studies with A549 lung cancer cells showed clear differences in the intra-cellular distributions of the fluorophores. The lipophilic carborane coumarin derivatives exhibited superior selectively within lipid droplets. In contrast, the polar boronic acid hydrazone-coumarins displayed intracellular localisation within the endoplasmic reticulum. A library of boron-containing rhodamine-like probes were also synthesised. All compounds exhibited near-infrared emission wavelengths with large Stokes shifts. Furthermore, modifications to the terminal boron moiety were not found to impact the overall red-shift of the molecules, although increasing the donor group strength favourably enhanced this shift. The low brightness of some of the probes, related to rhodamine spirocyclisation, meant that conclusive intracellular localisations could not be confirmed. The near-IR emitting nature of the rhodamine-like probes was recognised as a highly advantageous tool for bioimaging applications. Two fluorescent-labelled ligands with varying linker lengths, of the allosteric adamantyl benzamide P2X7R antagonist were prepared, based on the para-MIDA ester rhodamine-like fluorophore. Both probes were utilised in preliminary fluorescence studies, whereby the near-IR emitting nature of the fluorophore was retained despite conjugation to biomolecules. As well, a longer emission wavelength was observed with a shorter linker length. This research ultimately highlights the versatility of boron as a unique element in fluorescence and biological imaging applications

Sewage sludge heavy metal analysis and agricultural prospects for Fiji

Insoluble residues produced in Waste Water Treatment Plants (WWTP) as by products are known as sewage sludge (SS). Land application of SS, particularly in agricultural lands, is becoming an alternative disposal method in Fiji. However, currently there is no legislative framework governing its use. SS together with its high nutrient and organic matter contents, constitutes some undesired pollutants such as heavy metals, which may limit its extensive use. The focus of this study therefore was to determine the total concentrations of Pb, Zn, Cd, Cu, Cr, Ni and Mn in the SS produced at the Kinoya WWTP (Fiji) and in the non-fertile soil amended with the SS at 20, 40, 60, 80% application rates and in the control (100% Soil). The bioavailable heavy metals were also determined as it depicts the true extent of metal contamination. The treatment mixtures were then used to cultivate cabbage plants in which the total heavy metal uptake was investigated. Total Zn (695.6 mg/kg) was present in the highest amounts in the 100% SS (control), followed by Pb (370.9 mg/kg), Mn (35.0 mg/kg), Cu (65.5 mg/kg), Cr (20.5 mg/kg) and finally Cd (13.5 mg/kg) and hence a similar trend was seen in all treatment mixtures. The potential mobility of sludgeborne heavy metals can be classified as Ni > Cu > Cd > Zn > Mn > Cr > Pb. Total metal uptake in plant leaves and stems showed only the bioavailable metals Cu, Cd, Zn and Mn, with maximum uptake occurring in the leaves. Ni, despite being highly mobile was not detected, due to minute concentrations in the SS treatments. Optimum growth occurred in the 20 and 40% SS treatments. However maximum Cu and Mn uptake occurred in the 40% SS treatment thereby making the 20% treatment the most feasible. Furthermore the total and bioavailable metal concentrations observed were within the safe and permitted limits of the EEC and USEPA legislations