Multifunctional Fluorescent Microgel‐Embedded Hydrogels for Temperature and X‐Ray Sensing

Abstract Stimuli‐responsive aggregation‐induced emission luminogen (AIEgen)‐based hydrogels exhibit tunable fluorescent signals in response to external stimuli, providing a suitable platform for sensing. As the largest sensory organ in the body, the response of skin temperature and X‐ray dosage is crucial in predicting and diagnosing a range of diseases, and effective cancer radiotherapy. In this study, dual‐responsive hydrogels are prepared by incorporating ratiometric fluorescent AIEgen‐based microgels into polyvinyl alcohol (PVA). Experimental and molecular dynamics (MD) simulation results indicate that the AIEgen‐based microgels enhance the mechanical and adhesive strength of the PVA hydrogels while maintaining good biocompatibility. Variations in temperature or X‐ray exposure affect the chemical structure of the co‐monomer or disulfide/diselenium‐containing crosslinkers, which influences the molecular motion of the synthesized AIEgen; the other fluorescent molecules are unaffected. Consequently, the ratiometric fluorescent signals emitted by the AIE microgel‐embedded hydrogels exhibit spectral and visual variations in response to changes in temperature and X‐ray exposure. Applying support vector machine (SVM) regression, the hydrogel can achieve improved spectral accuracy. The hydrogel is shown to accurately sense skin temperature and effectively map radiotherapy dose levels.