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No description available.

Phthalocyanines are a group of molecules, which have been studied extensively due partly to their use and potential in a wide variety of applications, but also on account of the seemingly endless list of differently substituted moieties, which in principle may be prepared. The history of the compounds in general are discussed briefly in Chapter 1 of this thesis, while Chapter 2 focuses on Photodynamic Therapy, an area in which they have more recently been found to exhibit excellent potential. The synthesiso of novel phthalocyanines for potential application in PDT is reported in Chapter 3. The current research investigated the synthesis of binuclear Pcs from the linking of two preformed phthalocyanine rings by means of an oxalyl bridge functionality and also from the mixed cyclisation of phthalonitriles with bisphthalonitriles, which proved to be extremely problematic. The synthesis of water-soluble phthalocyanine derivatives was investigated as a sideline, which resulted in the synthesis of a novel phthalocyanine monomer substituted with eight triethylene glycol chains. Efforts to synthesise a phthalocyanine linked to a glucose unit were unsuccessful. Chapter 4 describes research into the photophysical properties of a number of mononuclear and binuclear phthalocyanines synthesised both in the current work and also compounds synthesised by co-workers. The electronic absorption and fluorescence spectra of the compounds are investigated, and the absorption spectrum of a purely cofacial dimeric structure is obtained by calculation from the spectrum of one of the binuclear derivatives. Laser Flash Photolysis was performed on a number of the samples, determining triplet lifetimes, triplet quantum yields and singlet oxygen quantum yields. The effect of aggregation on the photoproperties of phthalocyaninesis investigated in Chapter 5. The current work involved low temperature absorption and fluorescence spectroscopy on a number of mononuclear and binuclear phthalocyanine derivatives. The nature of the aggregated structures, which were observed to form at 77K, are then rationalised with reference to previous research into phthalocyanine aggregates and crystal structures.

No description available.

No description available.

Yes / Boron dipyrromethene derivates (BODIPYs) are promising photosensitisers (PSs) for cancer treatment using photodynamic therapy (PDT). This study investigates the functionalisation of graphene oxide (GO) with a BODIPY derivate for glutathione (GSH) depletion and PDT. The functionalisation of GO with a 3,5-dichloro-8-(4-boronophenyl) BODIPY via a diol derivatisation with the phenyl boronic acid moiety at the meso position of the BODIPY core, allowed to preserve the intrinsic properties of GO. We demonstrated that both chlorine atoms were substituted by GSH in the presence of glutathione transferase (GST), inducing a relevant bathochromic shift in the absorption/emission features and thus generating the active PS. Ex vitro assessment using cell lysates containing cytoplasmatic GST revealed the intracellular catalytic mechanism for the nucleophilic substitution of the GO-BODIPY adduct with GSH. Confocal microscopy studies showed important differences in the cellular uptake of free BODIPY and GO-BODIPY and revealed the coexistence of GO-BODIPY, GO-BODIPY-GS, and GO-BODIPY-GS2 species inside vesicles and in the cytoplasm of the cells after 24 h of incubation. In vitro biocompatibility and safety of GO and GO-BODIPY were evaluated in 2D and 3D models of prostate adenocarcinoma cells (PC-3), where no toxicity was observed up to 100 µg ml−1 of GO/GO-BODIPY in all treated groups 24 h post-treatment (cell viability > 90%). Only a slight decrease to 80% at 100 µg ml−1 was observed after 48 h of incubation. We demonstrated the efficacy of a GO adduct containing an α-chlorine-substituted BODIPY for the simultaneous depletion of intracellular GSH and the photogeneration of reactive oxygen species using a halogen white light source (5.4 mW cm−2) with a maximum in the range of 500–800 nm, which significantly reduced cell viability (<50%) after irradiation. Our study provides a new vision on how to apply BODIPY derivates and potentiate the toxicity of PDT in prostate and other types of cancer.

Biocatalysis is becoming an increasingly attractive alternative to more traditional chemical transformations for use in pharmaceutical and industrial applications. This interest is primarily a consequence of the high regio-, stereo- and enantioselectivity that is associated with enzyme catalysed reactions. However, the proliferation of such techniques has been limited due to the dependence of enzyme activity upon the presence of redox cofactors, which are typically expensive and must be used in conjunction with efficient regeneration systems. Whilst numerous methods have been described, of particular potential are those that employ exogenous photosensitisers as a means of generating reducing equivalents to promote catalytic turnover. In this study the potential of transition metal complexes as photosensitisers towards the development of light-driven biocatalytic systems is evaluated. Use of such compounds gives great scope towards fine-tuning the spectral and redox properties of the sensitisers with the aim of optimising catalytic efficiency. Detailed herein is an extensive study towards the synthesis and characterisation of a range of ruthenium(II) and iridium(III) coordination compounds. Using NMR, UV-vis, and electrochemical techniques, all complexes were fully characterised and the origins of the photophysical properties further investigated using time-dependent density functional theory (TD-DFT) calculations. A series of ruthenium compounds were synthesised containing the bis(2,2′-bipyrazyl)ruthenium(II) moiety, investigating the impact of changes made to the functionality of the ancillary ligand upon the overall properties of the complex. New synthetic procedures have been developed towards the preparation of both 2,2′-bipyrazine and the related complexes, exhibiting significant benefits over previously established methods. Through manipulating the electron density of the ancillary ligand it is shown that the redox properties may be effectively tuned upon inducing changes in the energy of the metal-based HOMO. The utilisation of cyclometalated iridium(III) complexes in aqueous systems has been limited due to a poor water solubility that is typically associated with these compounds. Herein it is demonstrated that this issue may be effectively circumvented on inclusion of the positively charged pyridinium moiety. Upon incorporation of this functional group into either the cyclometalating or ancillary ligands, two distinct series of compounds were successfully prepared. Complexes of the substituted quaterpyridinium ligands possess complicated UV-vis spectra that exhibit low intensity absorbance up to 650 nm. A number of monoquaternised bipyridinium compounds were also utilised as pyridine derived N-heterocyclic carbene cyclometalating ligands, to afford a range of complexes with unique redox properties. The prepared photosensitisers were subsequently used to induce catalytic turnover in light-driven biocatalytic systems utilising the flavin dependent oxidoreductase enzymes, pentaerythritol tetranitrate reductase (PETNR) and the thermophilic old yellow enzyme (TOYE). Through an extensive investigation, optimal reaction conditions have been identified and a mechanism of electron transfer proposed. These systems were successfully implemented in the reduction of a broad range of substrates under both aqueous and biphasic conditions, delivering yields and enantiomeric excesses comparable to those obtained utilising an enzyme coupled regeneration system. This study clearly demonstrates that transition metal complexes are excellent candidates in developing practical light-driven biocatalytic systems. It is expected that, with further investigation, this approach can be readily expanded to incorporate a variety of applications and provide an effective alternative to the use of costly redox cofactors and a reliance upon complex regeneration techniques.

Espécies de fungos dos gêneros Candida e Trichophyton e Cryptococcus neoformans são os mais importantes agentes causadores de micoses em humanos. A seleção de linhagens tolerantes aos fungicidas atualmente utilizados torna extremamente necessário o desenvolvimento de novas estratégias para o controle desses patógenos. A inativação fotodinâmica (IF) de fungos baseia-se na utilização de um fotossensibilizador (FS) que se acumula preferencialmente nas células-alvo e que pode ser ativado por exposições à luz visível. A ativação do FS induz a formação de espécies reativas de oxigênio que matam a célula fúngica. O uso de FS para o tratamento de micoses é uma aplicação recente e promissora da IF de fungos. No presente estudo, foram avaliados os efeitos dos tratamentos fotodinâmicos (TF) com os FS fenotiazínicos azul de metileno (MB), azul de toluidina (TBO), novo azul de metileno (NMBN), o derivado pentacíclico do azul de metileno S137 e com uma cloroalumínio ftalocianina em nanoemulsão (ClAlPc/NE) nas leveduras Candida albicans, C. glabrata, C. krusei, C. parapsilosis, C. tropicalis, Cryptococcus neoformans e nos microconídios dos dermatófitos Trichophyton mentagrophytes e T. rubrum. Os efeitos dos TF com os diferentes FS fenotiazínicos também foram avaliados na linhagem celular L929 de camundongo. Inicialmente, a eficácia dos TF foi avaliada pela determinação da concentração inibitória mínima (CIM) de cada FS para cada dose de luz. Adicionalmente, nas condições otimizadas, também foram determinados os efeitos dos TF na sobrevivência das diferentes espécies de fungos. Os MICs variaram tanto entre FS como entre espécies e diminuíram com o aumento da dose de luz. Entre os FS fenotiazínicos, para a maioria dos tratamentos (espécies e doses de luz), o NMBN e o S137 apresentaram os menores MICs. Os MICs para o NMBN e para o S137 foram <= 2,5 ?M para todas as espécies de Candida, para doses >= 20 J cm-2. MICs para a ClAlPc/NE foram tão baixos quanto 0,01 ?M para algumas das espécies de Candida. O TF com NMBN e S137 resultaram em redução de pelo menos 3 logs na sobrevivência de todas as espécies de Candida e de Trichophyton. O TF com ClAlPc/NE resultou em redução de até 4 logs na sobrevivência de C. albicans e C. tropicalis e de até 6 logs na sobrevivência de células melanizadas de C. neoformans. A internalização da ClAlPc foi confirmada por microscopia confocal de fluorescência e a quantidade incorporada pelas células foi dependente da concentração do FS. As toxicidades relativas entre os diferentes FS para as células de mamífero foram semelhantes às observadas em fungos, por exemplo maior toxicidade e fototoxicidade do NMBN e do S137 comparada às do MB e TBO / Fungal species of the genera Candida and Trichophyton and Cryptococcus neoformans are the main responsible for mycoses in humans. The selection of fungal strains resistant to currently used fungicides makes the development of alternative fungus-control techniques highly desirable. Fungal photodinamic inactivation (PI) is based on the use of a visible light-activate photosensitiser (PS) that preferentially accumulates in the cell of the target microorganism. The activation of the PS starts photochemical processes that produce a series of reactive oxygen species (ROS) that kill the fungal cell. The use of PS to treat mycoses is a novel and promising application of PI. In the present study, the effects of the photodynamic treatments (PDT) with the phenothiazinium PS methylene blue (MB), toluidine blue O (TBO), new methylene blue N (NMBN), the novel pentacyclic photosensitiser S137 and with a chloroaluminum phthalocyanine nanoemulsion (ClAlPc/NE) on the yeasts Candida albicans, C. glabrata, C. krusei, C. parapsilosis, C. tropicalis and Cryptococcus neoformans and on microconidia of the dermatophytes Trichophyton mentagrophytes and T. rubrum were evaluated. The effects of the PDT with the phenothiazinium PS were also evaluated on the mouse fibroblast cell line L929. The efficacies of the PDT were evaluated initially by determining the minimal inhibitory concentration (MIC) of each PS for each light dose. Additionally, for the optimized conditions, the effects of the PDT on the survival of the different fungal species were also determined. MICs varied both among PS and species and decreased with light dose increase. Among the phenothiazinium PS, for most treatments (species and light doses), NMBN and S137 showed the lowest MICs. MICs for NMBN and S137 were <= 2.5 ?M for all the Candida species to light doses >= 20 J cm-2. MICs for ClAlPc/NE were as low as 0.01 ?M for some of the Candida species. PDT with NMBN and S137 resulted in a reduction of at least 3 logs in the survival of all Candida and Trichphyton species. PDT with ClAlPc/NE resulted in reductions up to 4 logs in the survival of C. albicans and C. tropicalis and up to 6 logs in the survival of C. neoformans melanized cells. Internalization of ClAlPc by C. neoformans was confirmed by confocal fluorescence microscopy, and the degree of uptake was dependent on PS concentration. The relative toxicities among the different PS to mammalian cell were similar to the antifungal data, i.e. greater toxicity and phototoxicity with NMBN and S137 compared to MB and TBO.

Espécies de fungos dos gêneros Candida e Trichophyton e Cryptococcus neoformans são os mais importantes agentes causadores de micoses em humanos. A seleção de linhagens tolerantes aos fungicidas atualmente utilizados torna extremamente necessário o desenvolvimento de novas estratégias para o controle desses patógenos. A inativação fotodinâmica (IF) de fungos baseia-se na utilização de um fotossensibilizador (FS) que se acumula preferencialmente nas células-alvo e que pode ser ativado por exposições à luz visível. A ativação do FS induz a formação de espécies reativas de oxigênio que matam a célula fúngica. O uso de FS para o tratamento de micoses é uma aplicação recente e promissora da IF de fungos. No presente estudo, foram avaliados os efeitos dos tratamentos fotodinâmicos (TF) com os FS fenotiazínicos azul de metileno (MB), azul de toluidina (TBO), novo azul de metileno (NMBN), o derivado pentacíclico do azul de metileno S137 e com uma cloroalumínio ftalocianina em nanoemulsão (ClAlPc/NE) nas leveduras Candida albicans, C. glabrata, C. krusei, C. parapsilosis, C. tropicalis, Cryptococcus neoformans e nos microconídios dos dermatófitos Trichophyton mentagrophytes e T. rubrum. Os efeitos dos TF com os diferentes FS fenotiazínicos também foram avaliados na linhagem celular L929 de camundongo. Inicialmente, a eficácia dos TF foi avaliada pela determinação da concentração inibitória mínima (CIM) de cada FS para cada dose de luz. Adicionalmente, nas condições otimizadas, também foram determinados os efeitos dos TF na sobrevivência das diferentes espécies de fungos. Os MICs variaram tanto entre FS como entre espécies e diminuíram com o aumento da dose de luz. Entre os FS fenotiazínicos, para a maioria dos tratamentos (espécies e doses de luz), o NMBN e o S137 apresentaram os menores MICs. Os MICs para o NMBN e para o S137 foram <= 2,5 ?M para todas as espécies de Candida, para doses >= 20 J cm-2. MICs para a ClAlPc/NE foram tão baixos quanto 0,01 ?M para algumas das espécies de Candida. O TF com NMBN e S137 resultaram em redução de pelo menos 3 logs na sobrevivência de todas as espécies de Candida e de Trichophyton. O TF com ClAlPc/NE resultou em redução de até 4 logs na sobrevivência de C. albicans e C. tropicalis e de até 6 logs na sobrevivência de células melanizadas de C. neoformans. A internalização da ClAlPc foi confirmada por microscopia confocal de fluorescência e a quantidade incorporada pelas células foi dependente da concentração do FS. As toxicidades relativas entre os diferentes FS para as células de mamífero foram semelhantes às observadas em fungos, por exemplo maior toxicidade e fototoxicidade do NMBN e do S137 comparada às do MB e TBO / Fungal species of the genera Candida and Trichophyton and Cryptococcus neoformans are the main responsible for mycoses in humans. The selection of fungal strains resistant to currently used fungicides makes the development of alternative fungus-control techniques highly desirable. Fungal photodinamic inactivation (PI) is based on the use of a visible light-activate photosensitiser (PS) that preferentially accumulates in the cell of the target microorganism. The activation of the PS starts photochemical processes that produce a series of reactive oxygen species (ROS) that kill the fungal cell. The use of PS to treat mycoses is a novel and promising application of PI. In the present study, the effects of the photodynamic treatments (PDT) with the phenothiazinium PS methylene blue (MB), toluidine blue O (TBO), new methylene blue N (NMBN), the novel pentacyclic photosensitiser S137 and with a chloroaluminum phthalocyanine nanoemulsion (ClAlPc/NE) on the yeasts Candida albicans, C. glabrata, C. krusei, C. parapsilosis, C. tropicalis and Cryptococcus neoformans and on microconidia of the dermatophytes Trichophyton mentagrophytes and T. rubrum were evaluated. The effects of the PDT with the phenothiazinium PS were also evaluated on the mouse fibroblast cell line L929. The efficacies of the PDT were evaluated initially by determining the minimal inhibitory concentration (MIC) of each PS for each light dose. Additionally, for the optimized conditions, the effects of the PDT on the survival of the different fungal species were also determined. MICs varied both among PS and species and decreased with light dose increase. Among the phenothiazinium PS, for most treatments (species and light doses), NMBN and S137 showed the lowest MICs. MICs for NMBN and S137 were <= 2.5 ?M for all the Candida species to light doses >= 20 J cm-2. MICs for ClAlPc/NE were as low as 0.01 ?M for some of the Candida species. PDT with NMBN and S137 resulted in a reduction of at least 3 logs in the survival of all Candida and Trichphyton species. PDT with ClAlPc/NE resulted in reductions up to 4 logs in the survival of C. albicans and C. tropicalis and up to 6 logs in the survival of C. neoformans melanized cells. Internalization of ClAlPc by C. neoformans was confirmed by confocal fluorescence microscopy, and the degree of uptake was dependent on PS concentration. The relative toxicities among the different PS to mammalian cell were similar to the antifungal data, i.e. greater toxicity and phototoxicity with NMBN and S137 compared to MB and TBO.

S'ha estudiat el desenvolupament de fotosensibilitzadors i la seva formulació en teràpia fotodinàmica. S'han caracteritzat les propietats fotofísiques dels fotosensibilitzadors porficènics. S'han proposat diferents estratègies tals com la introducció de grups carboxilat en la perifèria o ions de metalls pesants en el nucli, per millorar el disseny de nous fotosensibilitzadors basats en el macrocicle porficènic. Entre ells, el temocè (m-THPPo), el porficè anàleg a la temoporfina, mostra excel•lents propietats fotofísiques, fotoestabilitat i alta eficàcia fotodinàmica. A causa de la seva alta hidrofobicitat, s'ha desenvolupat una formulació liposomal per a l'administració in vitro i in vivo del temocè. m-THPPo/DPPC/DMPG (1:67.5:7.5 relació molar) té alta eficiència d'encapsulació mantenint les seves propietats tant fotofísiques com a biològiques. El temocè liposomal va exhibir l'eficàcia fotodinàmica in vitro més alta per molècula internalitzada, sent un sistema d'administració de fàrmacs eficaç per a una estratègia in vivo dirigida a les cèl•lules tumorals. El temocè encapsulat en micel•les de Cremophor EL va mostrar una mínima internalització cel•lular. Consistentment, la formulació micel•lar va mostrar millor la resposta in vivo quan s'utilitza en un règim vascular. Amb la finalitat de minimitzar la internalització del fotosensibilitzador en les cèl•lules normals, es van proposar liposomes decorats amb lligands folat. Aquesta estratègia resulta en una internalització dues vegades major dels liposomes dirigits al receptor folat respecte a la corresponent formulació no específica. Finalment, han estat explorats nous models cel•lulars in vitro per a l'optimització dels processos amb oxigen singlet. Els cultius cel•lulars en 3D reprodueixen l'heterogeneïtat d'oxigen i fotosensibilitzador que està present en els teixits reals, proporcionant informació molt útil per interpretar i predir el resultat de la teràpia fotodinàmica. També s'ha demostrat la capacitat de desactivació de l'oxigen singlet d'antioxidants en un model ex vivo de pell porcina. / Se ha estudiado el desarrollo de fotosensibilizadores y su formulación en terapia fotodinámica. Se han caracterizado las propiedades fotofísicas de los fotosensibilizadores porficénicos. Se han propuesto diferentes estrategias tales como la introducción de grupos carboxilato en la periferia o iones de metales pesados en el núcleo, para mejorar el diseño de nuevos fotosensibilizadores basados en el macrociclo porficénico. Entre ellos, el temoceno (m-THPPo), el porficeno análogo a la temoporfina, muestra excelentes propiedades fotofísicas, fotoestabilidad y alta eficacia fotodinámica. Debido a su alta hidrofobicidad, se ha desarrollado una formulación liposomal para la administración in vitro e in vivo del temoceno. m-THPPo/DPPC/DMPG (1:67.5:7.5 relación molar) tiene alta eficiencia de encapsulación manteniendo sus propiedades tanto fotofísicas como biológicas. El temoceno liposomal exhibió la eficacia fotodinámica in vitro más alta por molécula internalizada, siendo un sistema de administración de fármacos eficaz para una estrategia in vivo dirigida a las células tumorales. El temoceno encapsulado en micelas de Cremophor EL mostró una mínima internalización celular. Consistentemente, la formulación micelar mostró mejor la respuesta in vivo cuando se utiliza en un régimen vascular. Con el fin de minimizar la internalización del fotosensibilizador en las células normales, se propusieron liposomas decorados con ligandos folato. Esta estrategia resulta en una internalización dos veces mayor de los liposomas dirigidos al receptor folato respecto a la correspondiente formulación no específica. Por último, han sido explorados nuevos modelos celulares in vitro para la optimización de los procesos con oxígeno singlete. Los cultivos celulares en 3D reproducen la heterogeneidad de oxígeno y fotosensibilizador que está presente en los tejidos reales, proporcionando información muy útil para interpretar y predecir el resultado de la terapia fotodinámica. También se ha demostrado la capacidad de desactivación del oxígeno singlete de antioxidantes en un modelo ex vivo de piel porcina. / The photosensitizer and formulation development in photodynamic therapy have been studied. They have been characterized the photophysical properties of new porphycene-based photosensitizers. Different strategies such as the introduction of carboxylate groups in the periphery or heavy metal ions in the core have been proposed for improving the design of novel photosensitizers based on the porphycene macrocycle. Among them, temocene (m-THPPo), the porphycene analogue to temoporfin, shows excellent photophysical properties, superior photostability and high photodynamic efficiency. Owing to its high hydrophobicity, a liposomal formulation has been developed for in vitro and in vivo administration of temocene. m-THPPo/DPPC/DMPG (1:67.5:7.5 molar ratio) yielded high encapsulation efficiency maintaining its photophysical and biological properties. Liposomal temocene exhibited the highest in vitro killing efficacy per uptaken molecule and they were an efficient drug delivery system for in vivo tumor cell targeting strategy. Temocene encapsulated in Cremophor EL micelles showed minimal cell internalization. Consistently, micellar formulation showed the best in vivo response when used in a vascular regime. In order to minimize the internalization of the photosensitizer in normal cells, liposomes decorated with folic acid ligands were proposed. This strategy leads to a 2-fold higher uptake of folate-targeted liposomes than the corresponding non-targeted formulation. Finally, new in vitro cellular models for a better optimization of singlet oxygen-involved processes were explored. 3D cellular cultures reproduced the oxygen and photosensitizer heterogeneity found in real tissues, providing useful information to interpret and predict the photodynamic therapy outcome. The singlet oxygen quenching ability of antioxidants in ex vivo porcine skin model has also been demonstrated.