Peptide aerogels comprising self-assembling nanofibrils

Bioinspired molecular self-assembly is a popular route to novel functional materials for industrial applications. Here we explore, for the first time, the possibility of using organogel and hydrogels of short self-assembling beta-sheet-forming peptides, as starting states for the creation of nanostructured peptide aerogels. The effects of supercritical fluid drying (SCF) and freeze-drying (FD) on the nanofibrillar peptide gel network were investigated. SCF processing was found to cause collapse of peptide organogel networks, presumably because of peptide insolubility in carbon dioxide (CO₂). Freeze-drying of peptide hydrogels proved a more efficient method of removing the solvent without destroying the self-assembled fibrillar network, leading to a microscopic aligned lamellar structure consisting of thousands of stacked peptide nanofibrils. These chiral, nanostructured, low-density aerogels are characterised by chemical versatility and regular display of functional groups on their surface. Appropriately designed peptides can also be triggered to self-assemble in situ inside other porous structures and impart biological-like functionality for catalysis, sensing, separation and filtration applications, or tissue engineering.