Peptide-based lipid mimetics with tunable core properties via thiol-alkyne chemistry

Thiol-alkyne chemistry is utilized to produce peptide-based A(2)B star polymers. This topography resembles a phospholipid where the polypeptide B block represents a functional, polar head group and the A blocks represent lipophilic units. We utilize a convergent, modular approach to produce lipid mimetics through conjugation of poly(L-glutamic acid) with three different lipophilic moieties (octadecane, cholesterol and polyhedral oligomeric silsesquioxane). All samples are shown to self-assemble in aqueous solution into pH-responsive vesicles. The self-assembly and pH-responsiveness were characterized using circular dichroism spectroscopy and light scattering. Detailed light scattering experiments determined that the aggregation number of the vesicles remains nearly constant as a function of pH, suggesting that the pH-responsiveness is a result of both the helix-coil transition as well as a change in chain packing at the vesicle interface.