Designing Peptide-Polymer Novel Composite Hydrogels for Biomedical Applications

  • Andong Liu

Student thesis: Phd

Abstract

Hydrogels and elastomer films are widely used in biomedical applications. Polyethene glycol (PEG) and short self-assembling peptides are commonly used to design new materials due to their biocompatibility. As a result, peptide-PEG conjugates have recently attracted significant interest in developing a novel hydrogel system combining the properties of both building blocks. Fibre formation is a key aspect of the gelation process of self-assembling peptide systems. Unwanted fiber lateral aggregation and assembly often form large fiber bundles, leading to very stiff non-transparent hydrogels and, in some extreme cases, phase separation [1]. These effects can limit the usage of peptide hydrogels in many areas[1], [2]. In this work, we decided to conjugate PEG to a family of self-assembling peptides developed in our group to control fiber formation and lateral aggregation to control the hydrogel's physical properties. In this project, we were interested in exploring how the PEG addition to the peptide system affects the self-assembly and other properties, such as gelation, mechanical properties and transparency. For this purpose, we investigated the different molecular weights of PEG linked to the β-sheet-forming peptides, FEFKFEFKK(F9), namely F9-2PEG, F9-5PEG, and F9-10PEG, with PEG's molecular weight of 2000, 5000 and 10000g/mol respectively. Our results showed that the addition of the PEG did not affect the overall charge of the peptide, but PEG has some shielding effect, which could cover some side groups of the peptide, resulting in the decreased tendency for the formation of F9 fibers. Moreover, it significantly reduce the hydrophobic interaction between fiber and fiber. Therefore, the thick and short fiber formed in the pure conjugate system, and also reduced fiber association and aggregation and formation of huge bundles and, consequently, network crosslink. The PEG attachment also increases the system's mobility, resulting in the dynamic gelation behaviour and the slower recovery property of hydrogel. In addition, based on the block conjugate of the F9-PEG, we develop the long-chain KF9-PEG multiblock copolymer elastomer film with some extension of PEG monomers. They have good mechanical properties and thermal stability.
Date of Award1 Aug 2023
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorAlberto Saiani (Supervisor) & Lu Shin Wong (Supervisor)

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