Novel mitochondria-targeted viscosity probe based on a fluorescent rotatable xanthene-hemicyanine dyad

A novel mitochondria-targeted fluorescent probe MXSO based on a fluorescent rotatable xanthene-hemicyanine dyad for the detection of viscosity has been successfully designed and synthesized. The probe is able to permeate cell membranes and accumulate in the mitochondria, which is convenient to use for monitoring the changes of mitochondrial viscosity in the living cell.