Development of functionalised fluorophores for sensing applications

Abstract

As our knowledge of the human body and health and disease grows, comes the need for new tools to study cellular function and dysfunction at the molecular level. This requires that research is focussed on the development of new fluorescent probes for cellular studies, including those that are both selective to an analyte and targeted to a specific organelle. This thesis describes advances in the development of dual-functionalised coumarins and the application of new coumarin-based tools.

Chapter Two focuses on the investigation and work towards a coumarin-based modular toolkit for dual-functionalised probes. Preliminary studies into suitable methods for facile functionalisation are presented. Potential dual-functionalised scaffolds are also explored.

Chapters Three and Four detail the application of the probes synthesised in Chapter Two. Chapter Three describes different methods to append hypoxia sensing units onto a fluorophore core and the evaluation of these probes. A targeted version was also investigated and applied to tumour spheroids to evaluate its use as a hypoxia stain for tumours. Chapter Four focuses on the development of a fluorescent array to discriminate between toxic and functional amyloids which are involved in diseases. This chapter describes the development of a two-sensor array and its application to discriminate between different amyloids. The array could also discriminate between different Alzheimer disease model mouse brain homogenate samples.

Chapter Five investigates the requirements for successful lysosomal targeting. Previous investigations in the New group have found that the commonly used lysosomal targeting moiety, the morpholine, is not very reliable. This chapter focuses on investigating the properties required for a successful lysosomal probe. Probes bearing one or two morpholine groups were synthesised and their lysosomal targeting abilities evaluated within cells, and this was related to their chemical and physical properties.