Investigating the co-assembly of amphipathic peptides.

Self-assembling peptide hydrogels (SAPHs) are increasingly recognised for their potential in biomedical and bioelectronic applications, with recent work focusing on exploiting the understanding of molecular self-assembly across the length scales. The resulting soft hydrogel materials are typically formulated by exploiting the self-assembly of short peptides into fibrillar aggregates that entangle and associate into networks. As more complex systems are thought to be needed to accommodate the needs of various applications, the mixing of peptides to form mixed SAPHs has come to the fore as a potential approach to design new systems with tailored and functional properties. This strategy has raised the question of whether mixing peptides with different chemical structures results in co-assembly or the formation of distinct fibrillar aggregates. In this work, we have used the FITC/Dabcyl FRET pair to investigate the co-assembly of a set of amphipathic short peptides. Our results show that the occurrence of co-assembly is affected the peptides' physicochemical properties, in particular solubility and hydrophobic residue side-group nature.