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.