Sensing and imaging of mitochondrial viscosity in living cells using a red fluorescent probe with a long lifetime.

A red fluorescent probe (Mito-V) with a long lifetime was designed to monitor viscosity changes with high selectivity and sensitivity. The fluorescence intensity and lifetime of Mito-V displayed a good relationship with the viscosity value, and Mito-V was successfully applied to sensing mitochondrial viscosity changes in living cells under different biological processes.