Hierarchical Organization of Purely Peptidic Amphiphiles into Peptide Beads

A broad range of new properties is emerging from supramolecular aggregates as they pass beyond the limitations of simple molecules. Self-assembled structures of purely peptidic amphiphiles may exploit such properties to produce biocompatible, smart materials for drug administration. In aqueous media, the solid-phase derived amphiphilic undecapeptide described herein (Ac-X(3)-gT) forms self-assembled particles of spherical shape with diameters between 200 and 1500 nm, termed "peptide beads". The beads result from hierarchical organization of micellar-like structures, a fact determined by a combination of investigations carried out by electron and atomic force microscopy (AFM), static and dynamic light scattering, and small-angle X-ray scattering. These highly ordered structures agree with the concept of multicompartmentization and represent the first example of supramicellar assemblies based purely on peptides. New structural insights, as presented here, allow a better understanding of the beads' capacity to embed hydrophobic and hydrophilic payloads and therefore provide new perspectives for drug delivery applications that may result from this new class of material.