Peptide Self-Assembled Nanostructures with Distinct Morphologies and Properties Fabricated by Molecular Design

Six surfactant-like peptides with the same amino acid composition but different primary sequences are designed, including G3A3V3I3K3, K3I3V3A3G3, I3V3A3G3K3, K3G3A3V3I3, V3G3I3A3K3, and K3A3I3G3V3. These peptides form antiparallel β-sheets during self-assembly. Because the constituent residues have different side chain size and hydrophobicity, sequence changes adjust group distribution and hydrophobicity on the two sides of a given β-sheet. This consequently tunes the binding energy of the side-to-side pairing conformations and leads to different self-assembled structures. G3A3V3I3K3 and K3I3V3A3G3 form short nanorods with diameters of 8.5 ± 1.0 nm and lengths <150 nm. I3V3A3G3K3 and K3G3A3V3I3 form nanosheets with heights of 4.0 ± 0.5 nm and limited lengths and widths. V3G3I3A3K3 and K3A3I3G3V3 form long fibrils with diameters of 7.0 ± 1.0 nm and lengths of micrometer scale. These nanostructures exhibit different capacity in encapsulating insoluble hydrophobic drug molecules and delivering them into the ...