The hydrogelation of self-assembling peptides involves two processes: 1. self-assembly of the peptides into fibres and 2. self-assembly of the fibres into 3-dimentional percolated networks. While significant efforts has been dedicated to elucidate the self-assembly of short peptides into fibres, the self-assembly of the fibres into networks has been little investigated, despite the fact that the topology of the network formed is a key factor influencing the final properties, in particular mechanical, of peptide hydrogels.<br/>We have investigated how to engineering the properties of β-sheet forming peptides hydrogel by manipulating the topology of the fibrillary network formed. The work exploits the peptide design developed by Zhang et al. which is based on the alternation of hydrophobic/hydrophobic residues. The self-assembly of these peptides results into the formation of a β-sheet fibre in which all the hydrophobic residues are located in the core of the fibre, therefore controlling the fibre morphology and stability, while all the hydrophilic residues are located on the surface of the fibre and therefore control the inter-fibre interactions and the topology of the network. By changing the type and nature of the residues on these peptides we were able to control the topology of the network formed and to fine tune the shear thinning and mechanical properties of the hydrogels (Figure 1). This was achieved by using a number of strategies from modifying one hydrophobic residue in the core of the fibre to design highly kinked fibres which association and aggregation tendency of reduced resulting in weaker hydrogels to inserting highly interacting hydrophilic residues on the surface of the fibres, such as arginine, that promote strong fibre-fibre aggregation resulting in stronger hydrogels.<br/>Through this fine control over the properties of these materials we were able to design highly tuned hydrogels for a variety of applications ranging from sprayable system for buccal drug delivery to injectable hydrogel for cell culture and regenerative medicine applications.

Engineering peptide hydrogels: From fibres to networks

253rd National Meeting (2017)

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