A matter of charge: Electrostatically tuned coassembly of amphiphilic peptides

Coassembly of peptide biomaterials offers a compelling avenue to broaden the spectrum of hierarchically ordered supramolecular nanoscale structures that may be relevant for biomedical and biotechnological applications. In this study we present a comprehensive exploration of binary coassembly leveraging amphiphilic and oppositely charged, anionic and cationic, -sheet peptides, which may give rise to a diverse range of coassembled forms. Mixtures of the peptides exhibit a notably diminished critical assembly concentration (CAC), in comparison to the corresponding values of the pure peptides. Intriguingly, the sweet spot for coassembled fibril formation was found to require excess of the cationic peptide whereas equimolar mixtures of the peptides exhibited the maximum folding into β-sheet structures. Mixtures of the peptides coassembled sequentially from solutions at concentrations surpassing each peptide's intrinsic CAC, were also found to require a higher portion of the cationic peptide to stabilize hydrogels. This study illuminates a systematic exploration of complementary charged -sheet peptides. The results may be relevant to the fundamental understanding of such intricate assembly systems and to the formulation of peptide-based nanostructures with diverse functionalities.