Abstract:
Knowledge of the many factors influencing the formation and stability of boron complexes in biological systems is limited. The aim of this research is to develop an O-BODIPY probe as a tool for the fluorescent labelling of sugars that could be applied to the interrogation of polysaccharide fine structure and the detection of cell-surface disease markers. The novel approach to binding sugars taken in this research project is based on the fact that boronic acids readily bind to diol moieties on sugars. Recent success substituting fluorine on BODIPY with other moieties such as methoxy provided a starting point for this work.
Chapter 1 provides background information on how sugars are classified and introduces the terminology associated with carbohydrate chemistry. It then goes on to give a brief overview of work that has been done using boronic acids to bind saccharides as boronate esters for structural determination and sensing applications. The chapter ends with an overview of BODIPY chemistry and the proof of concept experiments that this work is based on.
Chapter 2 reports on the synthesis and characterisation of the mesityl-O-BODIPY and its subsequent binding to glucose in a transesterification reaction. The O-BODIPY-glucose conjugates are characterised and their structures determined using HRMS, UV-vis and fluorescence spectroscopy and NMR spectroscopy supported by DFT calculations.
Chapter 3 describes tests that were done on the O-BODIPY-glucose reaction in an effort to gain insight into the reaction mechanism. In order to study the composition of the reaction mixture during the Knowledge of the many factors influencing the formation and stability of boron complexes in biological systems is limited. The aim of this research is to develop an O-BODIPY probe as a tool for the fluorescent labelling of sugars that could be applied to the interrogation of polysaccharide fine structure and the detection of cell-surface disease markers. The novel approach to binding sugars taken in this research project is based on the fact that boronic acids readily bind to diol moieties on sugars. Recent success substituting fluorine on BODIPY with other moieties such as methoxy provided a starting point for this work.
Chapter 1 provides background information on how sugars are classified and introduces the terminology associated with carbohydrate chemistry. It then goes on to give a brief overview of work that has been done using boronic acids to bind saccharides as boronate esters for structural determination and sensing applications. The chapter ends with an overview of BODIPY chemistry and the proof of concept experiments that this work is based on.
Chapter 2 reports on the synthesis and characterisation of the mesityl-O-BODIPY and its subsequent binding to glucose in a transesterification reaction. The O-BODIPY-glucose conjugates are characterised and their structures determined using HRMS, UV-vis and fluorescence spectroscopy and NMR spectroscopy supported by DFT calculations.
Chapter 3 describes tests that were done on the O-BODIPY-glucose reaction in an effort to gain insight into the reaction mechanism. In order to study the composition of the reaction mixture during the course of the reaction, a sampling protocol was developed and HPLC was used to separate and track the amounts of the conjugates over time.
Chapter 4 expands the sugars being tested with the O-BODIPY to include xylose, ribose, galactose, mannose and fructose. The resulting O-BODIPY-sugar conjugates were isolated and characterised so that patterns in binding behaviour could be identified. During the course of these tests, various limitations of the BODIPY were revealed that required refinement.
Chapter 5 describes the synthesis of a modified asymmetric A-O-BODIPY used to overcome the limitations of the original O-BODIPY. This new BODIPY had the desired properties and successfully reacted with galactose, mannose and fructose with more selectivity than O-BODIPY did.
Chapter 6 discusses the potential applications of this research to the interrogation of polysaccharide fine structure and the detection of cell-surface disease markers before summarising and evaluating the outcomes of the project.