Amphiphilic cylindrical copolypeptide brushes as potential nanocarriers for the simultaneous encapsulation of hydrophobic and cationic drugs

Cylindrical copolypeptide brushes PLLF-g-(PLF-b-PLG) with poly(l-lysine-co-l-phenylalanine) (PLLF) as the backbone and poly(l-phenylalanine)-b-poly(l-glutamic acid) (PLF-b-PLG) as the side chains have been synthesized and evaluated as drug delivery carriers. The synthesized copolypeptide brushes were characterized by 1H NMR, gel permeation chromatography (GPC), and transmission electron microscopy (TEM). In aqueous solution, the copolypeptide brushes adopt cylindrical morphologies and resemble unimolecular polymeric micelles with a hydrophobic poly(l-phenylalanine) core and a hydrophilic poly(l-glutamate) shell. An encapsulation study demonstrated that these water soluble, biodegradable copolypeptide brushes encapsulate hydrophobic compounds and cationic hydrophilic guest molecules simultaneously. Furthermore, the encapsulated cationic model compounds exhibit a pH-responsive releasing property.