Enhanced stability of core-surface cross-linked micelles fabricated from amphiphilic brush copolymers.

"Stealth" nanoparticles made from polymer micelles have been widely explored as drug carriers for targeted drug delivery. High stability (i.e., low critical micelle concentration (CMC)) is required for their intravenous applications. Herein, we present a "core-surface cross-linking" concept to greatly enhance nanoparticle's stability: amphiphilic brush copolymers form core-surface cross-linked micelles (nanoparticles) (SCNs). The amphiphilic brush copolymers consisted of hydrophobic poly(epsilon-caprolactone) (PCL) and hydrophilic poly(ethylene glycol) (PEG) or poly(2-(N,N-dimethylamino)ethyl methacrylate) (PDMA) chains were synthesized by macromonomer copolymerization method and used to demonstrate this concept. The resulting SCNs were about 100 times more stable than micelles from corresponding amphiphilic block copolymers. The size and surface properties of the SCNs could be easily tailored by the copolymer's compositions.