Thermo-sensitive and photoluminescent hydrogels: Synthesis, characterization, and their drug-release property

Multifunctional hydrogels that simultaneously possess semi-interpenetrating networks structure, strong photoluminescence, and temperature sensitivity were successfully fabricated based on the crosslink of poly(acrylamide) (PAAm) in the presence of poly(N-isopropylacrylamide) (PNIPAM) and CdTe quantum dots (QDs) at a mild condition. With the increase of external temperature, the photoluminescence (PL) intensity and emission peak of the hydrogels gradually decreased and red-shifted, respectively. Decreasing the temperature, the PL intensity and emission peak of the hydrogels could back to their initial values again. Moreover, drug-release experiments on the multifunctional hydrogels demonstrated that the release rate can be tuned by the environmental temperature and the content of PNIPAM. In addition, biocompatible hyperbranched polyglycerol functionalized QDs (QD@HPGs) instead of pristine QDs can also be incorporated into the hydrogels, affording biocompatible hydrogels which could still exhibit temperature-sensitive photoluminescence and drug-release behaviors.