Cyclopropyl Substituents Transform the Viscosity-Sensitive BODIPY Molecular Rotor into a Temperature Sensor

A quantitative fluorescent probe that responds to changes in temperature is highly desirable for studies of biological environments, particularly cellulo. Here, we report new cell-permeable fluorescence probes based on the BODIPY moiety respond environmental temperature. The were developed basis a well-established BODIPY-based viscosity by functionalization with cyclopropyl substituents at ? and ? positions core. In contrast parent fluorophore, ?-cyclopropyl-substituted fluorophore displays temperature-dependent time-resolved decays showing greatly diminished dependence, making it an attractive sensor be used lifetime imaging microscopy (FLIM). We performed theoretical calculations help rationalize effect photophysical behavior BODIPYs. summary, designed FLIM-based can sensing live cells.