NIR-Light- and pH-Responsive Graphene Oxide Hybrid Cyclodextrin-Based Supramolecular Hydrogels.

Here, a novel triple-responsive graphene oxide hybrid supramolecular hydrogel based on the electrostatic self-assembly between graphene oxide and a quaternized polymer and the host-guest inclusion between alpha-cyclodextrins and poly(ethylene glycol) monomethyl ether (mPEG) was constructed. The quaternized polymer was synthesized by quaternization between pH-sensitive poly(N,N-dimethylaminoethyl methacrylate) and bromine end-capped poly(ethylene glycol) monomethyl ether. The supramolecular hydrogels prepared from the host-guest inclusion of poly(ethylene glycol) monomethyl ether and alpha-cyclodextrins would turn into a mobile sol phase when the temperature was increased above a certain temperature (Tgel-sol). Graphene oxide sheets not only acted as a core material to provide additional cross-linking but also absorbed NIR light and converted NIR light into heat to trigger the gel-sol transition. The constructed graphene oxide hybrid cyclodextrin-based supramolecular hydrogels could respond to NIR light, temperature, and pH, which could be beneficial for controlled release of cargoes and would hold great promise in the field of delivery systems.