Phenylboronic Acid-Functionalized Copolypeptides: Facile Synthesis and Responsive Dual Anticancer Drug Release.

The incorporation of a phenylboronic acid group has appeared as an attractive strategy to build smart drug delivery systems. Here, we report novel synthesis of phenylboronic acid-functionalized copolypeptides based on an l-boronophenylalanine N -carboxyanhydride (BPA-NCA) monomer and their application for robust co-encapsulation and responsive release of dual anticancer drugs. By employing different poly(ethylene glycol) (PEG) initiators and copolymerizing with varying NCA monomers, linear and star PEG-poly(l-boronophenylalanine) copolymers (PEG-PBPA, star-PEG-PBPA), PEG-poly(l-tyrosine- co -l-boronophenylalanine) [PEG-P(Tyr- co -BPA)], PEG-poly(l-lysine- co -l-boronophenylalanine) [PEG-P(Lys- co -BPA)], and PEG-poly(β-benzyl-l-aspartate- co -l-boronophenylalanine) [PEG-P(BLA- co -BPA)] were obtained with controlled compositions. Interestingly, PEG-PBPA self-assembled into uniform micellar nanoparticles that mediated robust co-encapsulation and hydrogen peroxide (H 2 O 2 ) and acid-responsive release of dual antitumor drugs, curcumin (Cur) and sorafenib tosylate (Sor). These dual drug-loaded nanoparticles (PBN-Cur/Sor) exhibited a greatly enhanced anticancer effect toward U87 MG-luciferase glioblastoma cells. The facile synthesis of phenylboronic acid-functionalized copolypeptides from BPA coupled with their robust drug loading and responsive drug release behaviors make them interesting for construction of smart cancer nanomedicines.