One-Pot Fabrication of Pentapeptide Bio-Aerogel via Direct Alcogelation.

Bio-aerogels are a class of ultra-lightweight, extremely porous, solid materials that are engineered from biopolymers, e.g., polysaccharides, proteins, or peptides. Such biomaterials are of interest for medical and environmental applications, such as molecular filtration, wound healing, or tissue engineering. In this context, ultrashort peptides, defined as sequences of up to ten amino acids, are attractive self-assembling building blocks for bio-aerogels, due to their low-cost synthesis, chemical tunability, and potential biocompatibility. Building on our previous report demonstrating the intrinsic self-assembly of the human tachykinin Substance P into semi-flexible nanotubes, we focus on the tachykinin consensus sequence FFGLM-NH2, proposed here as the core motif driving native tachykinin self-assembly. Named tachycontide-1, the consensus pentapeptide can self-assemble into hydrogels and alcogels, a rare property for short peptides. As a result, the peptide aerogels can be fabricated by direct supercritical drying of a one-pot reaction mixture in ethanol. Using a set of biophysical techniques, including fluorescence spectroscopy, infrared spectroscopy, rheology, optical/electron microscopy, synchrotron small/wide-angle X-ray scattering, nitrogen adsorption-desorption analysis, and atomistic simulations, we examine the solvent influence on peptide self-assembly and its impact on the resulting aerogel structure, crystallinity, and physical properties.