An activatable NIR-I superoxide anion fluorescent probe selective for tracking cerebral ischemia-reperfusion injury

A series of nine near-infrared (NIR) fluorescent probes (DT-A1-DT-A8 and SWJT-37) was designed and synthesized featuring trifluoromethanesulfonate moieties as O₂^•- recognition groups. Through systematic testing, SWJT-37 emerged as the optimal NIR fluorescent probe, exhibiting high selectivity, remarkable sensitivity, and a 51-fold fluorescence enhancement towards O₂^•-. The probe demonstrated an exceptionally low detection limit (3.88 nM), surpassing most reported O₂^•- probes. SWJT-37 successfully enabled imaging of endogenous O₂^•- in HeLa and HT22 cells. More importantly, a significant increase in O₂^•- level was observed in a cerebral ischemia-reperfusion injury (CIRI) rat model using the probe, which indicating that SWJT-37 has been successfully applied in CIRI rat models.