Tetrazine-based AIE probes for specific detection of superoxide anion.

Combining the single-electron recognition property of tetrazine with aggregation-induced emission (AIE), two fluorescent probes named SWJT-48 and SWJT-49 were rationally designed and synthesized. This molecular design relied on a specific reduction recognition mechanism to eliminate interference from various substances. Both probes exhibited rapid response, high sensitivity and excellent selectivity toward superoxide anion (O2•-). Both exogenous and endogenous O2•- in HeLa cells were successfully detected using SWJT-49. Furthermore, SWJT-49 achieved fluorescence imaging of O2•- in HT22 cells via an oxygen-glucose deprivation (OGD) model that mimicked cerebral ischemia-reperfusion injury (CIRI). This design effectively eliminated the false-positive signals common in traditional fluorescent probes caused by aggregation and viscosity variations, while minimizing the false-negative signals caused by the background interference of nonspecific AIE aggregates.