Dextran microgels loaded with ZnO QDs: pH-triggered degradation under acidic conditions

We demonstrated an extremely facile way to fabricate inorganic–organic microgels with pH sensitivity and fluorescence. Aqueous dextran microgels are crosslinked by ZnO quantum dots (QDs). The ZnO@Dextran microgels were synthesized by simply mixing amino-modified ZnO (ZnO QDs) with carboxymethyl dextran (CMD) while stirring. The hybrid microgels showed an average diameter of ∼5 μm and strong fluorescence under ultraviolet (365 nm) irradiation. Up to 79.3 wt % of ZnO QDs were loaded into microgels. The ZnO QDs crosslinkage in the hybrid microgels structure enabled the microgels to degrade under mild acidic environment due to pH sensitivity of ZnO QDs. After loading of doxorubicin (Dox), the microgels were used as drug carriers for pH-controlled release of Dox. The degradation of the microgels and the release of loaded cargos could be monitored by detecting fluorescence intensity of the microgels. Moreover, owing to the cytotoxicity of ZnO QDs at their destination, drug-loaded ZnO@Dextran microgels can be used for synergistic therapy. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 45831.