APPLIED PHOTOPROPERTIES OF PHENYLENE ETHYNYLENES

Light-absorbing molecules can be used as powerful tools to perturb and understand biological systems by fluorescence, sensitization, or photochemical reactions. A thorough understanding of the delivery of dyes to specific biochemical targets and the processes that control the fate of excited-state energy is needed to engineer useful technology out of organic photochemistry. This thesis presents four projects investigating different aspects of pathogen destruction and biochemical sensing in a variety of systems, using the properties of p-phenylene ethynylenes (PEs), an especially flexible and well-studied class of conjugated molecules. Of particular relevance, some PEs are found to be effective dyes for amyloid protein aggregates both in solution and in mouse and human brain tissue. As well, control of the solvent microenvironment can be used to tune accessibility of the triplet state, which has implications for targeted photodynamic inactivation of both pathogens and cancer cells