pH-Responsive "Supra-Amphiphilic" Nanoparticles Based on Homoarginine Polypeptides.

pH-responsive "supra-amphiphiles" based on double hydrophilic, positively charged block copolypeptides such as PEG--poly-l-lysine together with low molecular weight stimuli-sensitive partners that contain phosphate and carboxylate groups have been widely studied. In contrast, the other widely used cationic polypeptide poly-l-arginine whose cell-penetrating properties are well-known has been much less explored for the synthesis of supra-amphiphile-based nanomaterials. It is also known that the guanidine side chain of arginine binds to carboxylate anions with binding constants that are 2.