Quencher-Delocalized Emission Strategy of AIEgen-Based Metal–Organic Framework for Profiling of Subcellular Glutathione

Distinguishing glutathione (GSH) level in different subcellular locations is critical for studying its antioxidant function in the signaling system. However, traditional methods for imaging subcellular GSH were achieved in isolated organelles or fixed cells. In this work, we report a quencher-delocalized emission strategy for in situ profiling of GSH at different subcellular locations in living cells. A nonemissive metal–organic framework (MOF) nanoprobe was designed with AIEgen as the linker and Cu^II as the node and quencher. The AIEgen in MOF structure was lightened up with green emission in a neutral environment due to partial Cu^II delocalization by competitive binding to GSH. Meanwhile, along with the protonation of AIEgen ligand under acidic environment, the AIEgen-based MOF could be completely dissociated in the presence of GSH to yield yellow emission. The two-channel ratiometric analysis of dual-colored emission of AIEgen-based MOF allows visualization of GSH in cytoplasm and lysosome in living cells, which is also able to report the drug effects on different subcellular GSH levels.