Dual-emission NIR fluorescent probe sensitive response biological microenvironment and sulfur dioxide

The viscosity and sulfur dioxide (SO2) of mitochondria are key indicators for changes in the cell microenvironment. At present, the emission wavelength of fluorescent probes responding to viscosity was relatively short. Among of them, fewer probes responded to both viscosity and sulfur dioxide. Herein, we developed a NIR (Near Infrared) fluorescent probe Mito-Th (740 nm) for simultaneous detecting SO2 and viscosity in mitochondria: N,N-dimethyl-4(thiophen-2-yl)-aniline acts as fluorescent rotors to regulate the twisted intramolecular charge transfer (TICT) process for achieving viscosity response; the C = C of indole salt linked to thiophene responding to the nucleophilic addition of SO2. Thus, the probe responded to viscosity and SO2 by red and blue fluorescence channels, respectively. More importantly, we have successfully applied the probe Mito-Th to monitor both viscosity and SO2 of mitochondria in cells and zebrafish, and revealed the relationship between viscosity and SO2 during mitochondrial dysfunction. It will provide guidance for the regulation of mitochondrial dysfunction.