Responsive Supramolecular Microgels with Redox-Triggered Cleavable Crosslinks

We demonstrate a novel method to synthesize aqueous microgels with supramolecular redox-cleavable crosslinks. The redox-cleavable crosslinker was synthesized on the basis of host-guest interactions using methacrylate-modified beta-cyclodextrin (host) and vinylferrocene (guest). A series of microgels with variable contents of a redox-cleavable crosslinker were synthesized via precipitation polymerization. Synthesized supramolecular microgels exhibit hydrodynamic radii in the size range 100-200 nm in the swollen state at 20 degrees C. The increase of the temperature induces a volume-phase transition, leading to the deswelling of microgels. This temperature-induced swelling/deswelling is completely reversible and does not lead to the degradation of microgels. Using the combination of characterization methods such as light scattering and electron microscopy, we demonstrate that the obtained microgels can be degraded using chemical oxidants (FeCl3 or H2O2) or oxidation during bulk electrolysis. The degradation rate was studied by tracing the hydrodynamic radius, scattering intensity, and turbidity as a function of time. Furthermore, we could also demonstrate efficient loading and release of anticancer drug (doxorubicin) with UV-vis spectroscopy.