Self-Assembly of Enantiomeric Helical Dipeptides into Vesicles: Applications

The self-assembly of enantiomeric dipeptides, Fmoc-Gly-l-Phg-OMe (1, Phg: phenylglycine) and Fmoc-Gly-d-Phg-OMe (2) was examined. Both formed well-organized hollow nanovesicles in an acetonitrile-water (1:1) mixture, as observed in Field-Emission Transmission Electron Microscopy (FETEM) images. In the crystalline state, the peptides formed a parallel β-sheet arrangement and also self-associated into a single helix-like structure, generating void spaces through various supramolecular interactions. Two consecutive helical strands did not twist to form a double helix; instead, they extended in antiparallel (C-N and N-C) directions. The self-assembled nanostructures demonstrated remarkable thermal stability during dry heating and exhibited strong binding with bioactive drugs and dyes. Interestingly, both peptides showed selectivity in sensing Cr⁶⁺ ions. These peptides can encapsulate gold nanoparticles (AuNPs) in their self-assembled vesicles.