ABSTRACT Hydrogen sulfide (H 2 S) is a newly‐recognized gaseous signaling molecule and participates in a range of physiological and pathological processes. In this work, based on a molecular switch coupling an imine group with an adjacent H‐bond, we designed “turn‐on” aggregation‐induced emission (AIE)‐active fluorescent probes for H 2 S detection, designated as TSI series. To evaluate the substituents and electron effects on the molecular switch as well as H 2 S response, four TSI compounds bearing different substituents (HTSI, DFTSI, DPTSI, and DOTSI) were synthesized and compared in the performance of H 2 S sensing. Among all the probes, DPTSI achieves the best sensing performance toward H 2 S (> tenfold fluorescence enhancement). Building on these findings, a rational design strategy involving H‐bond protection/deprotection and electron‐donating group modifications can be employed for developing other probes based on the TSI platform. In further glioblastoma cell imaging assessments, DPTSI effectively lighted up glioblastoma cells with high contrast due to their elevated H 2 S levels, suggesting its potential as a practical tool for biological H 2 S sensing and glioma cell mapping in vivo.
Fang et al. (Fri,) studied this question.