Preparation of multicomponent systems as a means of controlling the properties of peptide-based low molecular weight hydrogels

Marshall, Libby Jane (2023) Preparation of multicomponent systems as a means of controlling the properties of peptide-based low molecular weight hydrogels. PhD thesis, University of Glasgow.

Abstract

Multicomponent systems can be used to achieve different properties and behaviors from low molecular weight gelators (LMWGs) that cannot be accessed from single component systems. In this thesis, we exemplify a number of interesting multicomponent systems. We cover many possible systems, mixing two gelators, mixing a gelator and a non-gelator and mixing a gelator and a cross-linking agent, all of which give different possibilities.

In Chapter 2, we use a two-component system, showing that a non-gelling component modifies the assembly of the gelling component, allowing access to co-assembled structures that cannot be formed from the gelling component alone. We characterised the systems across multiple length scales, from the molecular level by NMR and CD spectroscopy, to the microstructure level by SANS and finally to the material level using nanoindentation and rheology. By exploiting the enhanced mechanical properties achieved through addition of the second component, we formed multicomponent noodles with superior mechanical properties to those formed by the single component system. Furthermore, the non-gelling component can be triggered to crystallise within the multicomponent noodles, allowing us to prepare new types of hierarchical composite noodles.

In Chapter 3, we prepared a variety of multicomponent systems where both components are N-functionalised dipeptide-based LMWGs that may either co-assemble or self-sort. We exemplify how varying the concentration ratio of the two components can be used to tune the properties of the multicomponent system. We also investigated the effect of changing the chirality of a single component on the assembly of the systems. While predicting the outcome of multigelator assembly is a challenge, the preparation of a variety of systems allows us to probe the factors affecting their design.

In Chapter 4, we show that preparing multicomponent systems from a lysine- (K)-containing peptide-based LMWG and the cross-linking agent glutaraldehyde (GTA) allows tuning of the mechanical properties of the final gel depending on the position of the K residue in the peptide chain, whether the cross-linking agent is added to the system before or after gelation and whether gelation is triggered by a reduction in pH or by physical cross-linking with Ca2+ ions.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: Q Science > QD Chemistry
• Colleges/Schools: College of Science and Engineering > School of Chemistry
• Supervisor's Name: Adams, Professor Dave
• Date of Award: 2023
• Depositing User: Theses Team
• Unique ID: glathesis:2023-83655
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 16 Jun 2023 08:22
• Last Modified: 16 Jun 2023 08:32
• Thesis DOI: 10.5525/gla.thesis.83655
• URI: https://theses.gla.ac.uk/id/eprint/83655

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