Multifunctional 1,3-benzoxazole-merocyanine-based probe for the ratiometric fluorescence detection of pH/HSO3-/viscosity in mitochondria

pH, HSO3-, and viscosity are crucial bio-markers for evaluating the status of mitochondria in the cell micro - environment. With this research, we developed a ratiometric mitochondria-targeting fluorescent probe 1 that was responsive toward bisulphite, pH and viscosity. Hydroxylphenyl 1,3-benzoxazole (D) acted as a pH recog- nition unit; benzo[e]indolium (A) acted as a fluorescent rotor to achieve a viscosity response; the C-C bond constructed by bridging D and A was susceptible to nucleophilic attack and hence responded to HSO3-. Probe 1 exhibits significant ratiometric signal changes, high sensitivity, outstanding selectivity, and good stability for detecting pH, viscosity, and SO2 in solution. Probe 1 was used for imaging pH, viscosity, and SO2 derivatives in live cells and zebrafish, indicating its potential for identifying mitochondrial dysfunctions.

Automated summary

In this study, a ratiometric mitochondria-targeting fluorescent probe 1 was developed that could respond to bisulphite, pH, and viscosity. Probe 1 exhibited significant signal changes, high sensitivity, outstanding selectivity, and good stability for detecting pH, viscosity, and SO2 in solution. It was also used for imaging pH, viscosity, and SO2 derivatives in live cells and zebrafish, suggesting its potential for identifying mitochondrial dysfunctions.