Controlled ROMP Synthesis of Ferrocene-Containing Amphiphilic Dendronized Diblock Copolymers as Redox-Controlled Polymer Carriers

Novel well-defined redox-responsive Ferrocene (Fc)-containing amphiphilic dendronized diblock copolymers are synthesized by the ring-opening metathesis polymerization technique using Grubbs' third-generation olefin metathesis catalyst as the initiator. These dendronized block copolymers can self-assemble into spherical micelles in aqueous solution. The size of self-assembled micelles can be modulated by the composition (namely, the ratio of hydrophobic and hydrophilic segments) and concentration of the dendronized copolymers. The obtained micelles show reversible redox-controlled self-assembly behaviors using FeCl3 as oxidant and glutathione as reductant. Furthermore, the model molecule Rhodamine B is successfully loaded in these micelles, and the oxidation-triggered controllable release is achieved by changing the type of oxidants (FeCl3 and H2O2) and their concentrations. This is the first example of redox-responsive micelles self-assembled by novel amphiphilic dendronized Fc-containing block copolymers, and the present micelles are visualized to be potential candidates in many fields, especially in stimuli-responsive drug delivery systems.