Becauseo f the importance of phthalocyaninesa s functional materials and in medicine their synthesis and applications have been well documented in the literature. In the introductory chapter (chapter 1) a brief account of preparative methods and applications is outlined. Photodynamic therapy (PDT) is becoming a widely investigated area of research. Phthalocyanine drug candidates for PDT have received a great deal of interest. Novel aromatic, heteroaromatic and functionalised aromatic asymmetric 3: 1 phthalocyaninesw ere synthesisede, xploiting the Suzuki cross-coupling reaction. Systematic investigation into their possible use as PDT candidates was explored in chapter 2. As a result of unexpected interactions between pyridyl functionalised 3: 1 zinc phthalocyanines, further investigation into complexes of `edge-to-face' assembliesw as undertaken.T he synthesiso f these assembliesth rough Lewis acid/base interactions between the nitrogen lone pair and a metal centre has been investigatedb y 'H NMR spectroscopy.A pplication to both phthalocyaninea nd phthalonitrile compounds produced some interesting `supramolecular' assemblies. Finally, to further exploit these interactions a photoswitchable, selfassembledm onolayer wasp repared.T he monolayerw as designedt o isomerise under irradiation with light, to facilitate an `on-off type switch, that could bind a metal centred phthalocyanine.

No description available.

Photodynamic therapy (PDT) has been considered a favorable approach in certain oncology applications for its little invasiveness and better targeting specificity compared to conventional therapies. In PDT, localized photosensitizers can be activated by light to produce cytotoxic oxygen species. However, the prescribed drug and light doses do not provide satisfying outcomes as the PDT efficacy relies strongly on the interplay between localized dose factors. Therefore, the fluorescence emission from active photosensitizers has been investigated extensively for real-time PDT dosimetry. This dissertation focuses on characterizing fluorescence properties of two photosensitizers, Photofrin® and PpIX, in cellular models and discusses about their potential clinical applications. First, we introduc time-resolve fluorescence (TRF) of photosensitizers as a potential tool in PDT dosimetry. TRF acquires fluorescence decay profiles and it is sensitive to drug-microenvironment interactions that occur frequently in PDT. Therefore, it provides complementary information in addition to fluorescence spectra that could be subject to intensity artifacts. In this dissertation, we review TRF studies on PDT photosensitizers, and quantify TRF parameters of Photofrin® at various subcellular locations. Moreover, analytical solutions are developed to correct distorted TRF measurements from commonly used time-domain data acquisition. Second, we report a new concept – integrated detection and treatment of Barrett’s Esophagus (BE). BE is a pre-cancerous lesion considered as a major risk factor in developing esophageal cancers. However, early intervention of BE has remained a challenging issue as tissue biopsy introduces significant sampling errors and the separate procedures between diagnosis and treatment add relocation errors. We proposed to use PpIX fluorescence to highlight morphological features at the cellular level for quantitative classification, followed by well-characterized treatment. Current proof-of-concept studies were performed separately, whilst the detection and treatment can be integrated using confocal endomicroscopy technology. Overall, these studies examine the potential benefits provided by fluorescence of photosensitizers for cancer diagnosis and treatment monitoring. / Thesis / Doctor of Philosophy (PhD)

No description available.

Two-photon photo-activated functional molecules play key roles in a growing number of technological and biological applications as the availability of high powered, tuneable lasers increases. The development of new, strongly two-photon absorbing functional chromophores is key to the advancement of these technologies. A series of photoresponsive compounds including organic chromophores and transition metal coordination complexes were designed, synthesised and characterised by NMR, mass spectrometry, elemental analysis and X-ray crystallography. Photophysical characterisation of the compounds including electronic absorption spectroscopy, luminescence spectroscopy, luminescence lifetime studies and two-photon absorption (2PA) experiments were performed. Density functional theory (DFT) calculations were performed and supporting data are presented. Of particular interest is the use of photochromic materials to address the increasing demand for high-density data storage employing two-photon absorption for 3-dimensional control of excitation. Towards this, a series of four photochromic "push-pull" azobenzenes of donor-pie-acceptor structure containing a para-ethoxy donor substituent have been synthesized with varying strength of the acceptor group (para-NO2, CN, CO2Et, F). Kinetic studies of their one-photon photoisomerisation and thermal cis-trans isomerisation were performed in solution and in polymer films, and their non-linear two-photon trans-cis photoisomerisation was demonstrated. Luminescent metal centres offer the possibility of a fluorescent read-out mechanism for optical data storage, modulated by a photochromic ligand, which may quench fluorescence in one isomer and not the other. Two photochromic pyridyl azobenzene ligands were designed and synthesised and coordinated to Re(I), Pt(II) and Ru(II) polypridyl metal centres. The trans-cis photochromism of the ligands and complexes was investigated by one- and two-photon absorption. Luminescence modulation was demonstrated via photochromism of the coordinated ligand L2 for the Re(I) tricarbonyl bipyridyl complex ReL2 which displayed enhanced emission intensity in the cis form.2PA is also of interest for biological applications due to the longer, less damaging wavelengths used at which biological tissue is more transparent. Photodynamic therapy (PDT) is a non-invasive clinical treatment for cancers where a photosensitizer is optically excited to generate cytotoxic singlet oxygen, which kills cells in the area under irradiation. Platinum group transition metal complexes have been investigated for this purpose due to their strong 2PA properties and accessible low-lying triplet states, which make them efficient triplet-triplet energy transfer agents. A new cyclometallated Ir(III) complex bearing a fluorenyl phenanthroline ligand and a related bimetallic Ir(III)-Ru(II) complex were synthesised and assessed as two-photon singlet oxygen sensitizers. The monometallic Ir(III) complex was also shown to demonstrate PDT action by altering the morphology of C6 Glioma cells under 740 nm two-photon excitation.

1 / Tingting Feng

The vertebral column is the most common site of skeletal metastatic development secondary to breast cancer. Multiple clinical treatments are available for spinal metastasis, including systemic bisphosphonates and radiation therapy, however the success of current treatment approaches varies considerably. Alternative treatment strategies for spinal metastatic destruction must be aimed at both reducing tumor burden and restoring mechanical stability. Photodynamic therapy (PDT) has been shown to be successful at destroying osteolytic lesions in preclinical models of breast cancer spinal metastasis. However, the clinical feasibility of PDT for spinal metastasis is dependent on its potential effects on the structural integrity of vertebral bone. This thesis aims to determine the effects of PDT alone and in combination with bisphosphonate therapy on the structural architecture and mechanical properties of healthy and metastatically involved vertebrae. PDT was shown to have a positive effect on vertebral bone structure, alone and in combination with previous bisphosphonate therapy.

The vertebral column is the most common site of skeletal metastatic development secondary to breast cancer. Multiple clinical treatments are available for spinal metastasis, including systemic bisphosphonates and radiation therapy, however the success of current treatment approaches varies considerably. Alternative treatment strategies for spinal metastatic destruction must be aimed at both reducing tumor burden and restoring mechanical stability. Photodynamic therapy (PDT) has been shown to be successful at destroying osteolytic lesions in preclinical models of breast cancer spinal metastasis. However, the clinical feasibility of PDT for spinal metastasis is dependent on its potential effects on the structural integrity of vertebral bone. This thesis aims to determine the effects of PDT alone and in combination with bisphosphonate therapy on the structural architecture and mechanical properties of healthy and metastatically involved vertebrae. PDT was shown to have a positive effect on vertebral bone structure, alone and in combination with previous bisphosphonate therapy.

The skin acts as a protective barrier, is crucial for thermoregulation and also forms part of the sensory, immunological and endocrine system. Therefore skin preservation is paramount to preserving life. The loss of skin homeostasis, through injury, initiates the wound healing process where the final outcome is the formation of a scar. Scar treatment remains a challenge, despite a plethora of treatments, resulting in a poor outcome and sub-optimal response to existing therapies. Photodynamic therapy (PDT) has been used to treat oncologic conditions affecting the skin. Its action depends on a photosensitiser and a specific light source. Aminolevolinic acid (5ALA) and its methyl ester (MALA) are commonly used pro-drugs of the photosensitiser protoporphyrin IX (PpIX), which in combination with red light produces reactive oxygen species (ROS). ROS will cause different responses such as cell death and tissue destruction. There is limited clinical evidence emerging for the use of PDT in treating wound healing and pathological skin scarring. For this reason, further investigations are required to better understand the role of PDT in adult human skin wound healing and skin scarring. The aim of this investigation was to evaluate the accumulation of PpIX after exposure to 5ALA or MALA, phototoxicity of red light arrengment, citotoxicity, cell death inducction, ROS generation and a gene related analysis post-PDT in keloid fibroblasts compared to normal skin fibroblasts. Optimization of a wound healing organ culture (WHOC) model and evaluation of re-epithelialization, cell death, proliferation, extracellular matrix arreangment (ECM) and a related gene analysis after 5ALA-PDT ex vivo. General histology, cell death, proliferation, ECM rearrengment and a gene related analysis after PDT in skin scarring ex vivo. This investigation found PpIX accumulation higher with MALA compared to 5ALA. Phototoxicity and cytotoxicity was site specific within the lesion and increased proportionately to fluence rates. ROS generation leads to the decrease of cytoproliferation and increased apoptosis and necrotic cell death, COLI, COLIII an HSP70 were found down-regualted. Ex vivo wound geometry, system of support and growth media were optimized in a human wound healing organ culture (WHOC). WHOCs treated with 5ALA-PDT (20 J/cm2), showed an advancing re-epithelialization tongue 3.5 folds longer, which were highly proliferative, showing increased CK14 and p16 levels. The neo-epidermis was fully differentiated and neo-collagen was present. PCNA, p16, COLI, COLIII, MMP3, MMP19 and alpha-SMA were significantly more expressed in the dermis. MALA/5ALA-PDT (40 J/cm2) applied to striae alba, fine line, hypertrophic and keloid scars ex vivo coused an increased of apoptosis while proliferation decreased, matrix components were found to be re-organised, both according to the severity of the scar. COLI and COLIII genetic expression decreased while MMP3 and tropoelastin increased significantly. However, no statistically significant difference was observed between 5ALA and MALA-PDT treatments. In conclusion, this thesis shows that cytotoxicity post-PDT in KD fibroblasts is dependent on the lesional site within the scar, a precursor of intracellular photosensitiser and fluence. PDT in wound healing ex vivo shows increased re-epithelialization and ECM reconstruction and remodelling. Finally, in dermal fibrosis morphological and cellular effects of the application of PDT correlate with the degree and severity of dermal fibrosis. In view of this, PDT may be ideal for treating abnormal skin scarring and improving human cutaneous wound healing.

Orientador: Juliana Campos Junqueira / Banca: Antonio Olavo Cardoso Jorge / Banca: Aguinaldo Silva Garcez Segundo / Resumo: O objetivo do presente estudo foi avaliar os efeitos da terapia fotodinâmica, utilizando-se os fotossensibilizadores azul de metileno e azuleno associados ao laser em baixa intensidade, sobre cepas de Candida isoladas da cavidade bucal humana. Foram estudadas 20 cepas de Candida, sendo 5 C. albicans, 4 C. tropicalis, 4 C. glabrata, 2 C. parapsilosis, 2 C. kefyr, 1 C. krusei, 1 C. stellatoidea e 1 C. lipolytica. Cada cepa foi submetida a 6 condições experimentais: associação de laser em baixa intensidade com 660 nm e azul de metileno (L+AM+), associação de laser e azuleno (L+AZ+), irradiação com laser (L+F-), tratamento com azul de metileno (L-AM+), tratamento com azuleno (LAZ+) e tratamento apenas com solução fisiológica como controle (L-F-). Após o tratamento de cada cepa, foram realizadas diluições seriadas e semeaduras em ágar Sabouraud dextrose. Os dados de unidades formadoras de colônias (UFC/mL) foram submetidos à análise de variância e teste de Tukey (p<0,05). Os resultados demonstraram que todos os grupos tratados com laser (L+AM+, L+AZ+ e L+F-) apresentaram médias de UFC/mL (Log) inferiores aos grupos sem laser (L-AM+, L-AZ+ e L-F-). Os grupos com terapia fotodinâmica (L+AM+ e L+AZ+) apresentaram média de UFC/mL (Log) semelhante ou superior ao grupo L+F-. Concluiu-se que as cepas de Candida isoladas da cavidade bucal de pacientes submetidos à antibioticoterapia prolongada foram resistentes a terapia fotodinâmica com azul de metileno e azuleno nos parâmetros utilizados neste trabalho. / Abstract: The aim of this study was to evaluate the effects of the photodynamic therapy using methylene blue and azulene on isolated Candida strains of the oral cavity of patients who underwent a prolonged antibioticotherapy to treat lung tuberculosis. Twenty Candida strains were studied: 5 C. albicans, 4 C. tropicalis, 4 C. glabrata, 2 C. parapsilosis, 2 C. kefyr, 1 C. krusei, 1 C. stellatoidea and 1 C. lipolytica. Each strain underwent 6 experimental conditions: laser in combination with methylene blue (L+MB+), laser in combination with azulene (L+AZ+), irradiation with laser (L+P-), treatment with methylene blue (L+MB+), treatment with azulene (L+AZ+), and treatment with physiologic solution as a control group (L-P-). After the treatment of each strain, serial dilutions and spreading on Sabouraud dextrose agar were performed. Data from colony forming units per milliliter (CFU/ml) were analyzed by Tukey's test (p<0.05). The results showed that all the groups treated with laser (L+MB+, L+AZ+ and L+P-) presented the lowest mean CFU/ml (Log) value in relation to the groups treated without laser (L+MB+, L+AZ+ and L+F-). The groups treated with photodynamic therapy (L+MB+, L+AZ+) presented an average of CFU/ml (Log) similar or higher to the L+P- group. In summary, the results showed that isolated Candida strains of the oral cavity of patients who underwent a prolonged antibioticotherapy were resistant to the photodynamic therapy with methylene blue and azulene. / Mestre