Synthesis and Cross linking of L-DOPA Containing Polypeptide Vesicles

The synthesis and self-assembly of DOPA containing diblock copolypeptides into spherical vesicles is described. DOPA residues are naturally abundant in mussel adhesive proteins and are responsible for extensive covalent crosslinking of these materials upon oxidation. We found that vesicles could be formed from copolypeptides containing different amounts of DOPA substituted into hydrophobic segments, up to 100% DOPA content. The DOPA containing vesicles were covalently crosslinked in water using an oxidizing agent, in a process similar to the crosslinking of mussel adhesive proteins, which gave vesicles with dramatically improved membrane stability against freeze-drying, organic solvent, osmotic stress and complex media. These materials showed greatly enhanced membrane stability compared to non-crosslinked vesicles and have the advantage that the biomimetic crosslinker DOPA can be incorporated directly into the polypeptide sequence during synthesis.