Cyclodextrin-Responsive Micelles Based on Poly(ethylene glycol)–Polypeptide Hybrid Copolymers as Drug Carriers

Novel drug carriers based on poly(ethylene glycol) (PEG)?polypeptide copolymers, four-armed poly(ε-adamantane-l-lysine)2-block-poly(ethylene glycol)-block-poly(ε-adamantane-l-lysine)2 (PLys(Ad)2-b-PEG-b-PLys(Ad)2), have been prepared. The copolymers were synthesized via the ring-opening polymerization of amino acid N-carboxyanhydrides. The copolymers could spontaneously form core?shell micelles in aqueous solutions. It has been found that these micelles undergo triggered disassembly in response to an additional ?-cyclodextrin (?-CD). The in vitro drug release in response to ?-CD has been studied, and the result shows that the release of the entrapped drug doxorubicin (DOX) from the micelles could be accelerated by the addition of ?-CD. Their cytotoxicity and cell internalization behavior were also investigated in detail. These micelles are expected to have great potential in controlled drug release applications.