永盈会体育投注

Superoxide anion (O2??) is a key reactive oxygen species involved in oxidative stress–related diseases and is typically overproduced in tumor cells, making it an important biomarker for cancer diagnosis. Herein, we report a near-infrared (NIR) turn-on fluorescent molecular probe, Cy- O2??, for selective imaging of O2?? and precise tumor identification. Cy-O2?? is rationally designed based on a hemicyanine fluorophore, in which a trifluoromethanesulfonate group serves as a specific O2??-responsive recognition unit. In its intact form, fluorescence is effectively suppressed by blocking the intramolecular charge transfer (ICT) process. Upon reaction with O2??, nucleophilic attack at the sulfonyl sulfur induces O–S bond cleavage, releasing the free hemicyanine fluorophore, thereby recovering the NIR fluorescence signal (～742 nm). Cy-O2?? exhibits high sensitivity, excellent selectivity toward O2?? over other reactive species, and good biocompatibility. Cellular experiments demonstrate its capability to monitor endogenous and exogenous O2?? fluctuations. More importantly, in vivo imaging in tumor-bearing mouse models confirms precise tumor visualization, highlighting its potential for early tumor