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

Abstract

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.