Narcissistic Self-Sorting of Amphiphilic Collagen-Inspired Peptides in Supramolecular Vesicular Assembly

Herein, we describe the hierarchical self-assembly accompanying self-sorting of collagen-inspired peptides (CPs). The two amphiphilic CPs used in this study contained an azobenzene (Az) moiety at the N-terminal, connected through a flexible spacer, but with different lengths of the (Gly-Pro-Hyp) triplet (n = 5 and 7). When the CP aqueous solution (60 °C) was cooled to 4 °C, both CPs formed a triple helix structure and the pre-organized helices subsequently self-assembled into highly ordered vesicles with a diameter of 50-200 nm. Interestingly, narcissistic self-sorting was observed in both triple helix- and matured vesicle-formation processes, when the two CPs were mixed. Owing to the difference in the propensity for triple helix formation with temperature, the two CPs discriminate each other in response to a temperature change and form two kinds of triple helix foldamers, each containing a single component. The resulting differences in the amphiphilic balance and molecular length between the foldamers appear to allow individual self-sorting to form distinct vesicles. Furthermore, such vesicular assemblies were found to disassemble upon UV irradiation via trans-cis isomerization of the Az-groups. These findings offer important insights into the design of new complex but ordered, peptide self-assembly systems with potential applications in nanobiotechnology.