During the last decade, organic and supramolecular chemistry in combination with analytical and fluorescent-based sensing methods have led to the development of chemical biology tools to study protein phosphorylation in vitro. However, further challenges remain present to develop better chemical approaches that can allow us to understand the activation/inhibition of specific kinase pathways. To avoid the tedious process of developing individual highly selective receptors, the use of differential sensing techniques has been growing in the supramolecular chemistry field. This sensing protocol exploits the interactions between target analytes and a library of cross-reactive receptors to create a response pattern that is unique for individual analytes or different mixtures thereof. Using this approach, one obtains a distinct fingerprint of composite signals produced by the sensor elements allowing for discrimination of different kinases in vitro and in complex mixtures such as cell lysates. The main emphasis of this work sought to expand the current optical-based detection systems of phosphorylated proteins to include a new pattern-based recognition method for a new class of protein kinases. To this end, the synthesis of chemosensors and peptide-based biosensors was pursued to detect and differentiate relevant mitogen-activated protein (MAP) kinases which represent targets of pharmaceutical interest. Further, this research included the quantitative detection of MAP kinases and corresponding inhibitors using a combination of pattern recognition approaches with new chemometric tools. / text

Zinc is now firmly established as an essential trace element in the human body. Whilst it has many key structural and catalytic fixed roles, it is also found in 'mobile' pools in many essential organs and organelles that are readily chelatable. The presence and trafficking of these zinc pools are thought to contribute in some form to many human disease states associated with these organs, for example, Type 2 diabetes in the pancreas, some forms of cancer in the prostate, and even ischemic stroke, epilepsy and Alzheimer's disease. The exact role however, remains largely unknown and this is due to our current limitations with the methods in which we monitor the movement of this important element in our body. This thesis presents our efforts to develop novel Zn2+ selective chemosensors that can meet contemporary criteria for successful and simple imaging. Many efforts are being made to develop simple fluorescent molecular probes to monitor the trafficking and progress of Zn2+ through these cells and organs in real time via these chelatable 'mobile' pools. Chapter 1 will outline some successful efforts towards these and discuss their relevance and mechanisms of action, as well as outlining 'click'-chemistry and its role in chemosensing to date. Chapter 2 describes a novel 'click'-chemistry approach designed to aid with the simple construction of novel zinc-chelating probes in a facile and high yielding manner. This methodology was taken forward to the synthesis of 6 novel Zn2+-selective small molecule fluorescent probes that incorporate a cell organelle targeting motif in their structure. These are described in Chapter 3, and their successful testing both in-vitro and in-cellulo in murine pancreatic islet cells is presented and discussed. Finally, Chapter 4 discusses the development of some modified fluorescent [2]rotaxanes as molecularly interlocked architectures capable of binding and sensing metals, and will specifically focus on how small structural changes led to vast differences in their fluorescence properties, ultimately resulting in a Zn2+-selective [2]rotaxane in organic media.

Luminescent complexes of lanthanide ions are of growing interest because the long lifetime of emission allows time-resolved detection procedures to be employed. A key step in the development of such systems lies in the preparation of highly luminescent complexes which display high stability in aqueous solution. A series of ligands based on 1,4,7,10-tetraazacyclododecane have been prepared, in which the nitrogen atoms are appended with coordinating phosphinate or amide groups, or a combination of both. The compounds obtained are octadentate ligands which form water-soluble lanthanide complexes of high stability. Complexes incorporating aryl groups in the pendent arms have been prepared and some display intense metal luminescence following excitation into the organic chromophores. A back energy transfer process occurs in the terbium complexes containing naphthyl or quinohnone groups. Measurements of the luminescence lifetimes in H(_2)O and H(_2)O show diat diere are no metal-bound water molecules in the tetrabenzylphosphinate complexes. Those incorporating one amide and three phosphinate groups display hydration states between 0 and 1. An attempt has been made to correlate this information with that obtained from an analysis of the nuclear magnetic resonance dispersion profiles of related gadolinium complexes. The complexes incorporating secondary amide groups display an additional deactivation pathway for the metal excited state involving energy transfer into N-H bonds. The luminescence behaviour of four macrocyclic tetraamide ligands incorporating naphthyl fluorophores has been studied. These compounds exhibit distinctive changes in luminescence in the presence of quenching (eg. Pb(^2+), Cu(^2+) and Ni(^2+)) and non- quenching ions (eg. Cd(^2+) and Zn(^2+)). This behaviour extends to non-aqueous solution. The protonated tetranaphthyl ligand forms an intramolecular excimer in which the excimer emission displays a sensitive dependence on the polarity of die solvent.

The role of semiochemicals in the behaviour and biology of <I>Lepeophtheirus salmonis</I> was investigated using a range of techniques. The potential use of semiochemicals in the behavioural ecology of mobile stages was examined using longitudinal monitoring and experimental manipulation of laboratory reared single cohort populations. The chronic and long term effects of separation from the host were also investigated using similar populations. The nature and chemosensory capability of the sense system of the parasite was assessed through morphological and ultrastructural studies. Finally, the nature of potential chemical stimuli during initial copepodid settlement, pair formation and mating, and host re-attachment of mobile stages, was examined using both <I>in vitro</I> and <I>in vivo</I> techniques. Longitudinal monitoring of populations created a model for mobile development and the timing and processes of pair formation and mating. There was evidence of a hierarchy of pair formation between female stages, periods of strong mate competition between males, and many factors within the processes were defined. Survival off the host was strongly related to the developmental stage and/or size of the louse; with adult females surviving for the longest and preadult I males for the shortest periods. The ability of adult males to re-attach and subsequently persist on the host was significantly reduced after only 72 hours of separation. Very few potential chemosensory setae were found on the appendages examined, the exception to this being the antennule. Two distinct populations of setae on the distal (14 setae) and proximal (27 setae) articles of the antennule demonstrated a wide range of morphology. The internal organisation, innervation and ultrastructure of these antennular setae was examined in detail. The setae could be divided into at least 6 distinct categories, when the internal data were combined with the external morphology.

The presented dissertation encompasses three distinct investigations into novel complexes with diverse applications. Firstly, a Europium-based complex, K[Eu(hfa)4], exhibits remarkable potential for detecting dissolved CO2 in an ethylene glycol medium, offering a low limit of detection, rapid response times, and high signal-to-noise ratios. This complex demonstrates promise for quantifying CO2 concentrations and finds utility in sugar fermentation monitoring. Secondly, an innovative ratiometric optical sensor, Eu(tta)3([4,4'-(t-bu)2-2,2'-bpy)], showcases exceptional sensitivity and selectivity in detecting aluminum ions, making it suitable for environmental and biological applications. It exhibits reliable quantification in both methanol and aqueous samples, with remarkable accuracy validated by ICP-OES. Lastly, modifications to the Au3Pz3 complex synthesis enable the development of a silver ion sensor, paving the way for detecting silver ion leaching in real-life scenarios, such as silver nanoparticle-embedded bandages. The research extends to the synthesis of silver nanoparticles using various methods and foresees expanded in vitro and in vivo studies. These investigations collectively offer insights into the development of advanced sensing technologies with significant implications for a wide range of practical applications.

Thesis (PhD (Chemistry and Polymer Science))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Due to the adverse human health effects associated with mercury (Hg) toxicity, an innovative method for inorganic mercury (Hg2+) determination in aqueous solutions was investigated. The method of Hg2+ determination involved the use of a Hg2+ selective chemosensor immobilised onto an indium tin oxide (ITO) coated electrode in a photoelectrochemical cell. Upon light activation and in the presence of Hg2+ the fluorescent chemosensor absorbed a photon, and charge separation would occur according to the nature of the semiconductive material coated onto the ITO substrate. The charge separators and semiconductors investigated were an n-type carrier TiO2, polyaniline (PANI) and copolymers of polyaniline and 2-bromoaniline (P[A-co-2- BrA]s) with different monomer ratios. The polymer and copolymer coated ITO working electrodes used in the Hg2+ sensitive photoelectrochemical cell were electrochemically evaluated. The results demonstrated that the ITO coated with PANI had superior conductive and semiconductive properties compared to ITO coated with P[A-co-2-BrA]s. The ITO glass substrates were coated with TiO2, PANI or P[A-co-2-BrA]s, followed by the fluorescent chemosensor, a rhodamine 6G derivative (RS). The electrodes were subsequently photoelectrochemically evaluated in a photoelectrochemical cell in the presence of Hg2+. The PANI-RS coated electrode behaved as a photocathode in the presence of Hg2+ under illumination. The PANI-RS photoresponse increased with increasing Hg2+ concentration in the range 10 to 150 μg L-1, with a limit of detection of 6 μg L-1. ITO coated with TiO2 (ITO/TiO2) followed by a composite of PANI and RS had a linear photoanodic response in the Hg2+ concentration range of 10 to 200 μg L-1 and a limit of detection of 5 μg L-1. ITO and ITO/TiO2 coated with the P[A-co-2-BrA]s and RS had considerably lower photoresponses towards Hg2+ in aqueous solutions compared to PANI-RS. The photoresponses decreased with increasing 2-bromoaniline content. The PANI and P[A-co-2-BrA]s coated ITO and ITO/TiO2 electrodes were then also coated with another rhodamine 6G derivative with a thiolactone moiety (RT). The PANI coated electrode yielded a photocathodic response in the Hg2+ concentration range 0.2 to 5 μg L-1. ITO coated with TiO2 had no photoresponse towards Hg2+ due to repulsive forces between TiO2 and the RT molecules. The photoresponses of the working photoelectrodes towards Hg2+ were further evaluated in a custom photoelectrochemical Hg2+ detector. The photoresponses of PANI-RS and PANI-RT gave qualitative results for the presence of Hg2+ in aqueous solutions in concentrations as low as 2 μg L-1. / AFRIKAANSE OPSOMMING: Weens die negatiewe gesondheids aspekte toegeskryf aan Hg2+ vergiftiging is ‘n nuwe innoveerende metode van Hg2+ deteksie in wateroplossings ondersoek. Die voorgestelde metode van Hg2+ deteksie behels die gebruik van ‘n Hg2+ selektiewe chemosensor geimmobiliseer op ITO elektrodes in ‘n fotoelektrochemiese sel. Met lig aktivering en in die teenwoordigheid van Hg2+, absorbeer die fluoreseerende chemosensor ‘n foton, gevolg deur lading skeiding, soos bepaal deur die aard van die halfgeleidende material wat op die ITO platjies bedek is. Die halfgeleiers wat ondersoek was, was TiO2, PANI en ko-polimere van PANI met 2-bromoanilien. Die polimeer en kopolimeer bedekte ITO werkende elektrodes wat in die Hg2+ sensitiewe fotoelektrochemiese sel gebruik is, is elektrochemies geevalueer. Daaruit is gevind dat ITO bedek met PANI superieure geleier en halfgeleier eienskappe het in vergelyking met die ITO wat bedek is met P[A-co-2-BrA] kopolimere. Die ITO glas plaatjies is bedek met TiO2, PANI en die P[A-co-2-BrA] kopolimere gevolg deur die fluoresseerende chemosensor, RS. Die elektrodes is onderskeidelik fotoelektrochemies getoets in ‘n fotoelektrochemiese sel in die teenwoordigheid van Hg2+. Die PANI-RS elektrode het soos ‘n fotokatode opgetree in die teewoordigheid van Hg2+ onder beligting. Die foto-reaksie van die PANI-RS elektrode teeonoor Hg2+ het liniêr toegeneem van 10 μg L-1 tot 150 μg.L-1 met ‘n limiet van deteksie op 6 μg L-1. ITO/TiO2 wat bedek is met ‘n samestelling van PANI en RS het ‘n fotoanodiese reaksie gehad teenoor Hg2+ in die liniêre reeks van 10 tot 200 μg L-1 met ‘n deteksie limiet van 5 μg L-1. ITO en ITO/TiO2 bedek met die P[A-co-2-BrA] kopolimere het heelwat laer fotoreaksies getoon teenoor Hg2+ in waterige oplossings Die fotoreaksie het afgeneem met toeneemende 2-bromoanilien inhoud van die kopolimeer. Die PANI en P[A-co-2-BrA] kopolimere bedekte ITO en ITO/TiO2 elektrodes is verder bedek met ‘n tweede rhodamine 6G afgeleide, RT. Die ITO/PANI bedek met RT het weer ‘n fotokatodiese reaksie gehad teenoor Hg2+ in die konsentrasie interval 0.2 tot 5 μg L-1. Die ITO/TiO2 elektrode bedek met die PANI-RT samestelling het geen fotoreaksie gehad teenoor Hg2+ weens afstotende kragte tussen die TiO2 and RT molekules. Die fotoreaksies van die verskeie werkende elektrodes teenoor Hg2+ is verder getoets in ‘n tuisgemaakte fotoelektrochemiese Hg2+ detektor. Die fotoreaksies van die PANIRS en PANI-RT samestellings op ITO het kwalitatiewe resultate gelewer vir die teenwoordigheid van Hg2+ in waterige oplossings in konsentrasies tot so laag soos 2 μg L-1.

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La presente tesis doctoral titulada ¿Supramolecular and heterosupramolecular chemistry in controlled release and molecular recognition processes¿ está centrada en los dos aspectos principales de la química supramolecular que han experimentado un gran auge en los últimos años: el reconocimiento molecular y los procesos de liberación controlada. En particular la primera parte de la tesis se focaliza en el diseño y síntesis de moléculas orgánicas que pueden ser empleados cómo sensores para especies aniónicas y neutras. El paradigma seleccionado para los procesos de reconocimiento molecular fue la aproximación del dosimetro químico. Esta aproximación presenta ventajas con respecto a los otros dos métodos de determinación de aniones (desplazamiento y unidad coordinanteunidad indicadora), cómo, por ejemplo, la posibilidad de determinar los analitos en disolución acuosa. Así se sintetizaron dos sensores selectivos, uno para el anión fluoruro (F-) y el otro para glutatión (GSH). El sensor selectivo para la determinación de F- está basado en un colorante azoico funcionalizado, en su ¿OH fenólico, cómo silileter. Esta molécula presenta una banda de absroción muy intensa centrada a 350 nm que, después de la adición de F- , sufre un efecto hipocrómico significativo y un desplazamiento batocromico ligero (de ca. 10 nm), mientras aparece una nueva banda a 470 nm, determinando un cambio de incoloro a amarillorojo. Para obtener un sensor selectivo para GSH se sintetizó una sonda químico basado en una sal de 2,6-difenilpirilio. Sucesivamente se preparó una disolución de este compuesto en agua/CTAB, que se caracterizaba por un intenso color azul. En este caso, la adición de GSH produce una disminución significativa de la banda del visible, acompañada por la consecuente decoloración. Además la adicón de GSH induce la aparición de Resumen vi una intensa banda de emisión centrada a 485 nm (después de la irradiación a 350 nm). La segunda parte de esta tesis doctoral se basa en el diseño y síntesis de nuevos sistemas híbridos orgánicos-inorgánicos para procesos de liberación controlada en ambiente celular. Estos materiales híbridos se componen en general, de dos unidades: una matriz inorgánica mesoporosa de base silícea, capaz de almacenar moléculas orgánicas (colorantes, farmacos...) y un compuesto orgánico anclado covalentemente a la superficie externa del soporte inorgánico mesoporoso, que actúa cómo puerta molecular. La aplicación de un estímulo externo puede modificar la conformación de la puerta molecular permitiendo o bien impidiendo la difusión de la carga almacenada en los mesoporos hacía el exterior (disolución o citoplasma). El primer sistema sintetizado y estudiado se compone de una matriz inorgánica mesoporosa (MCM-41), cargada con el colorante Ru(bipy)3 2+ y funcionalizada en la superficie con un oligoetilen glicol mediante un grupo ester. La adición de la enzima esterasa determinaba la hidrólisis del grupo ester y la consecuente reducción del tamaño de la puerta molecular, acompañada por la liberación del colorante previamente cargado. Otro sistema de liberación preparado consiste en el uso de la misma matriz MCM-41 nanoscópica y el mismo colorante Ru(bipy)3 2+, pero se funcionalizó la superficie con una puerta molecular fotolabil. La irradiación en el maximo de absorción de la puerta molecular inducía la fotodegradación de la misma y la consecuente liberación del colorante. Un tercer ejemplo de sistema de liberación consiste en una puerta molecular caracterizada por la presencia de dos grupos funcionales hidrolizables con enzimas diferentes: grupos urea y amida. vii El material final, caracterizado por la presencia del mismo esqueleto inorgánico, y cargado con Ru(bipy)3 2+, era capaz de liberar selectivamente cantidades distintas de colorante, dependiendo del enzima empleado. Así se podían conseguir dos tipos de perfiles de liberación: uno muy rápido y poco intenso y otro más lento pero mucho mas intenso. Finalmente se sintetizó un material híbrido siempre basado en la misma matriz de MCM- 41, cargado con rodamina-B y funcionalizado en la superficie con galactooligosacáridos. Con este material se podía conseguir una liberación controlada del colorante selectivamente en células senescentes, debido a que estas sobreexpresan el enzima ß-galactosidasa que es capaz de hidrolizar los galactooligosacáridos. / Agostini, A. (2013). Supramolecular and heterosupramolecar chemistry in controlled release and molecular recognition processes [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/29397 / TESIS

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