An ESIPT-based fluorescent probe for visualizing pH dynamics during oxidative stress in living system

Cellular oxidative stress, characterized by excessive reactive oxygen species (ROS) production, disrupts cellular homeostasis and induces pH fluctuations within cells and organelles. Given the critical role of intracellular pH in maintaining homeostasis and regulating vital processes such as proliferation and enzyme activity, we designed and synthesized the benzothiazole-based fluorescent probe LYB-OH for pH monitoring. LYB-OH exhibits notably large Stokes shifts across various solvents, particularly in water where the Stokes shift exceeded 200 nm. Additionally, LYB-OH possessed good selectivity, stability, and reversibility in vitro. In biological imaging, the probe LYB-OH displayed low cytotoxicity and good imaging ability for different pH in cells. Furthermore, the probe enabled the visualization of pH changes in both cells and zebrafish induced by hydrogen peroxide and lipopolysaccharide. This provided an idea for the diagnosis of related diseases caused by intracellular pH fluctuations under oxidative stress.