The Formation of Polymer Vesicles or “Peptosomes” by Polybutadiene-block-poly(l-glutamate)s in Dilute Aqueous Solution

Abstract
Polybutadiene-block-poly(l-glutamate) copolymers were made by anionic polymerization and subsequent ring-opening polymerization of N-carboxyanhydrides and were characterized by NMR, IR, SEC, and circular dichroism. These polymers, when appropriately designed, form so-called “polymersomes” or “peptosomes”, vesicles composed of modified protein units. The size and structure of the vesicles are determined by dynamic light scattering, small-angle neutron scattering, and freeze-fracture electron microscopy. It is also shown that the size of the peptosomes does not depend on the pH; that is, the solvating peptide units can perform a helix−coil transition without serious changes of the vesicle morphology.