Real time precisely tracing the fluctuations of mitochondrial SO2 in cells during ferroptosis and tissues using a mitochondrial-immobilized ratiometric fluorescent probe

Mitochondrial sulfur dioxide (SO2) 2 ) plays important roles in physiological and pathological activities. Unfortunately, it is lack of a reliable tool to precisely visualize the mitochondrial SO2 2 and elaborate its complicated functions in various cytoactivities. Here we report a mitochondrial-immobilized fluorescent probe PM-Cl consisting of coumarin and benzyl chloride modified benzothiazole, which enables selective visualization of mitochondrial SO2 2 via chemical immobilization. The spectral results demonstrated that probe PM-Cl could respond to SO2 2 with high selectivity and sensitivity. Co-localization and the fluorescence of cytolysis extraction verified the excellent mitochondrial targeting and anchoring abilities. Due to the chemical immobilization, probe PM-Cl could firmly retain into mitochondria after stimulation of carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and H2O2. 2 O 2 . Significantly, a series of fluorescence images are indicative of capability for detecting the fluctuations of SO2 2 in mitochondria during ferroptosis. Furthermore, PM-Cl also could visualize SO2 2 in myocardium and muscle tissues after the stimulation of CCCP. Taken together, probe PM-Cl is a very potential molecular tool for precisely detecting mitochondrial SO2 2 to explore its complex functions in physiological and pathological activities.