Water-Alcohol Bigels from Fatty-Acylated Dipeptides

Peptide-based gels are emerging as an interesting class of biocompatible soft materials. Fmoc-protected amino acids and short peptides have gained considerable attention as promising gelators. Peptide amphiphiles, wherein an alkyl chain is appended to a polar peptidic moiety, is another important class of peptide-based gelators. Here we report the alcohol/water bigels formed by the rather simple fatty-acylated dipeptides wherein the peptidic moiety is made up of hydrophobic amino acids viz. Val, Ile, and Leu. Lauroyl, myristoyl, and palmitoyl were investigated as the N-terminal fatty acyl groups. None of the lauroylated peptides caused gelation of methanol/water and ethanol/water mixtures up to 2 wt% peptide concentration. Eight out of the 27 peptides resulted in distinct bigels. The gels are composed of fibrous aggregates as characterized by electron microscopy. Infrared spectroscopy suggests the β-sheet conformation of the peptidic region in the gels. Using Ma-IV ethanol/water bigel as the representativ...