Self-assembly and disassembly of a redox-responsive ferrocene-containing amphiphilic block copolymer for controlled release

Stimuli-responsive block copolymer micelles have recently emerged as promising drug delivery systems with controllable drug release. Herein, we report well-defined redox-responsive ferrocene-containing amphiphilic block copolymers PEG-b-PMAEFc, which were synthesized by the atom transfer radical polymerization (ATRP) of 2-(methacryloyloxy) ethyl ferrocene-carboxylate (MAEFc) using a PEG-based macro-ATRP agent. These block copolymers can self-assemble into various interesting nanostructures in aqueous solution. The self-assembled morphology of amphiphilic block copolymers is influenced by the nature of the common solvents used, the polymer composition and concentration, and the addition of β-cyclodextrin (β-CD) and redox agents (H2O2 and KMnO4), the effects of which were investigated by transmission electron microscopy (TEM) and dynamic light scattering (DLS). Furthermore, the redox agent H2O2 can be used to trigger the release of encapsulated cargo (Rhodamine B) in the polymeric nanocarriers. This redox behavior of the amphiphiles could open up an approach for redox-controlled drug delivery systems.