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Transparent Photochemistry: Infrared Photosensitizers and Singlet Oxygen Microscopy

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Transparent Photochemistry: Infrared Photosensitizers and Singlet Oxygen Microscopy Transparent Photochemistry: Infrared photosensitizers and singlet oxygen microscopy Elsa Fernanda Freitas da Silva Tese orientada por: Luís Guilherme da Silva Arnaut Moreira e Peter Remsen Ogilby Universidade de Coimbra Tese de Doutoramento em Química, especialidade Fotoquímica apresentada ao Departamento de Química da Faculdade de Ciências e tecnologia da Universidade de Coimbra. Coimbra, Julho de 2013 Acknowledgements This dissertation is the result of joint efforts, collaborations and help by many people. I want to express my appreciation to my supervisor, Professor Luis G. Arnaut, for his guidance, support and availability. His enthusiasm with science and motivation are an example to me. It has been a great pleasure to work in his group. To my group of colleagues in Coimbra: Rui Nunes, Gonçalo Sá, Ligia Silva, Hélder Tão, I want to thank you all for the support and fellowship. Specially, I want to thank Carlos Serpa for his availability to help and assistance me with the laser systems and, Fábio Schaberle for his assistance with photoacoustic calorimetry experiments and for been actively interested on my work providing me with great comments that were valued greatly. My special thanks to Professor Peter R. Ogilby for accepting to be my co-supervisor and give me the opportunity to work with different techniques in his laboratory in the University of Aarhus in Denmark. Peter valuable suggestions have greatly improved my scientific work. I have had a great time working in COMIs group. I want to thank all COMI group members whom I have encountered during my stay, for their great support and welcoming. Brian Wett for walking me through the laboratory on my first times. Rasmus Toftegaard, Jacob Arnbjerg, Lotte Holmegaard and Thomas Breitenbach for their excellent technical support. Frederico Pimenta and Gaby Bosio for supporting me with some long distance experiments, and Puk Lund for preparing cells. I would also like to thank Professor Mariette M. Pereira for kindly provided me compounds. Also, I have always found her support, availability and understanding. Carlos Monteiro, Sara Pinto, Vanessa Simões, Artur Abreu, for performing the synthesis of many of the compounds that I worked with. I thank João Pina and Professor Sérgio Melo for the single photon counting measurements. Krzysztof Kruczała for the EPR experiments and simulations. Janusz Dabrowski for receiving me in Krakow and give me his full support on the EPR experiments and discussion. Madalina M. Barsan for the cyclic voltammetry experiments. I thank Fundação para a Ciência e Tecnologia (FCT) for the financial support on my PhD scholarship SFRH/B46658/2008. Table of Contents Abstract .......................................................................................................................................... i Resumo ......................................................................................................................................... iii List of papers ................................................................................................................................. v Structures..................................................................................................................................... vii 1 Introduction .............................................................................................................................. 1 1.1 Tetrapyrrolic photosensitizers: porphyrins, chlorins and bacteriochlorins ......................... 3 1.2 Photodynamic therapy ......................................................................................................... 4 1.3 Photochemistry and photophysics of PDT .......................................................................... 7 1.4 Reactive oxygen species...................................................................................................... 9 1.4.1 Molecular oxygen: Ground state and excited state....................................................... 9 1.4.2 Quenching of sensitizer triplet states by molecular oxygen ......................................... 9 1.5 Cell death .......................................................................................................................... 12 1.6 Phototransformation of sensitizers .................................................................................... 13 1.8 References ................................................................................................................... 15 2 Photochemistry and photophysics of porphyrins and bacteriochlorins ............................ 19 2.1 Introduction ....................................................................................................................... 21 2.2 Results and discussion ....................................................................................................... 22 2.2.1 Absorption and fluorescence properties ..................................................................... 22 2.2.2 Generation of the triplet state ..................................................................................... 26 2.2.3 Singlet oxygen generation in solution ........................................................................ 35 2.2.4 Generation of radical species in solution ................................................................... 43 2.3 Conclusions ....................................................................................................................... 49 2.4 Materials and methods ...................................................................................................... 50 2.4.1 Materials ..................................................................................................................... 50 2.4.2 Methods ...................................................................................................................... 50 2.5 References ......................................................................................................................... 55 3 Photobleaching and photomodification of dyes ................................................................... 59 3.1 Introduction ....................................................................................................................... 61 3.2 Results ............................................................................................................................... 64 3.2.1 Photobleaching of photosensitizers with potential application in photodynamic therapy ................................................................................................................................. 64 3.2.1.1 Mechanistic considerations ..................................................................................... 70 3.2.2 Subcellular localization of porphyrins and bacteriochlorins in cells: Photobleaching, relocalization and photomodification. ................................................................................. 71 3.3 Conclusions ....................................................................................................................... 84 3.4 Materials and methods ...................................................................................................... 86 3.4.1 Materials ..................................................................................................................... 86 3.4.2 Methods ...................................................................................................................... 86 3.5 References ......................................................................................................................... 89 4 Detection of reactive oxygen species in mammalian cells ................................................... 93 4.1 Introduction ....................................................................................................................... 95 4.2 Results ............................................................................................................................... 97 4.2.1 Microscopy based singlet oxygen phosphorescence detection in single HeLa cells. 97 4.2.2 Cuvette-based singlet oxygen phosphorescence detection in cell suspensions ........ 106 4.2.3 Detection of oxygen radicals in cells ....................................................................... 110 4.2.4 Microscope based singlet oxygen detection – photobleaching considerations ........ 113 4.3 Conclusions ..................................................................................................................... 125 4.4 Materials and methods .................................................................................................... 127 4.4.1 Materials ................................................................................................................... 127 4.4.2 Methods .................................................................................................................... 127 4.5 References ....................................................................................................................... 132 5 Overall conclusion ................................................................................................................ 135 5.1 Overall conclusion........................................................................................................... 137 5.2 References ......................................................................................................................
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