Enzyme responsive self-assembled amphiphilic diblock copolymer synthesized by the combination of NMP and macromolecular azo coupling reaction

Abstract

Amphiphilic diblock copolymer with an azobenzene linkage has been synthesized by the combination of macromolecular azo coupling reaction and nitroxide-mediated radical polymerization (NMP). In this strategy, an azobenzene linkage would naturally establish at the copolymer junction of the amphiphilic diblock copolymer after the macromolecular azo coupling reaction. Self-assembly of this azobenzene linked copolymer in selected solvents can result uniform self-assembly aggregates. In the presence of enzyme azoreductase and coenzyme NADPH, the amphiphilic diblock copolymer chain will be broken by the cleavage of the azobenzene linkage, which will lead to the disruption of the self-assembly aggregates. UV–vis absorption spectra measurements indicated the release of Nile red, a hydrophobic dye, encapsulated by the self-assembly aggregates. Thus, the amphiphilic diblock copolymer with azobenzene linkage can potentially be applied for the fabrication of nanocarriers for colon-specific delivery purposes applications.