The Synthesis and Characterisation of Novel Low Molecular Weight Gelators and their Applications in Electrospinning to Develop Biocompatible Materials and Tissue Scaffolds

The work described in this thesis reports the design, synthesis and characterisation of novel compounds capable of acting as Low Molecular Weight Gelators (LMGWs). This class of compounds form self-assembled fibrous networks which entrap the solvent and form gels. These materials have received considerable attention in recent years due to a variety of applications that range from environmental to biomedical fields. Amphiphilic lipoamino acids, squaramides and carbohydrates are useful starting materials to synthesise LMWGs because they provide functional groups that can form the intermolecular interactions necessary for the formation of supramolecular self-assembled structures. Chapter 2 describes the synthesis and characterisation of amphiphilic derivatives of L-serine and their evaluation as LMWGs. This study shows how structural features, such as the functional groups in the side chain, or the length of the hydrocarbon chains affect their ability to form gels. These compounds were found to effect selective gelation of aliphatic or aromatic solvents. The lipoamino acids were also tested as phase selective gelators of organic solvents in biphasic aqueous mixtures. In addition, these compounds were used for the removal of aromatic pollutants from water. Chapter 3 describes the synthesis and characterisation of glycolipid derivatives of galactosyl, L and D/L (racemic) aspartic acid. Two families of glycolipids (O-linked and N-linked) were evaluated as LMWGs. It was found that structural features such as the chirality of the aspartic acid core or the nature of the glycosidic bond strongly affect the gelation ability and selectivity of these compounds. Chapter 4 describes the synthesis and characterisation of LMWGs from galactosylated amphiphilic squaramides. These compounds were found to be excellent gelators of mixtures of EtOH:H2O (1:1) and represent the first example of a glycosylated squaramide supramolecular gelator. Finally, Chapter 5 describes the application of the LMWGs discussed in previous chapters for the formation of PCL blended electrospun materials. The conditions to form electrospun fibres were optimised and their morphology and hydrophilic / hydrophobic character evaluated. In addition, preliminary studies determining the suitability of these materials as drug delivery systems and tissue scaffolds were carried out by our collaborators.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

National University of Ireland Maynooth

Year dc:date.issued

2018

Author dc:creator

• Ramos Ondono, Jessica

Language dc:language

en