Triggered Small-Molecule Release from Dual-Stimuli Responsive Microgels

Light- and temperature-responsive poly(N-isopropylacrylamide-co-nitrobenzyl methacrylate) (pNIPAm-co-NBMA) microgels were synthesized via free-radical precipitation polymerization and exhibited a hydrodynamic diameter of 320 ± 40 nm. We demonstrated that the microgels’ NMBA groups were cleaved upon UV irradiation, which we showed could be used for light-activated release of fluorescein (used as a model drug molecule). Moreover, drug release could also be promoted by microgel deswelling due to heating. Specifically, the hydrophobic model drug fluorescein was incorporated into the pNIPAm-co-NBMA microgels via physical interactions, and we showed that exposure to UV light (or heating) could induce its release. Thus, the pNIPAm-co-NBMA microgels could find the use for applications requiring triggered release of cargo when needed.