Construction of a polymer-based fluorescent probe with dual responsive sites for monitoring changes of lysosomal...

As highly dynamic organelles, lysosomes are involved in various physiological processes. The viscosity of lysosomes plays critical roles in maintaining their normal physiological function and abnormal variations of viscosity are associated with many diseases. Monitoring the changes of lysosomal viscosity could contribute to understanding lysosome-related physiological and pathological processes. In this work, based on an indole fluorophore and fluorescent polymer, poly(2-hydroxyethyl methacrylate) (PHEM), a new polymeric fluorescent probe, In-PHEM, with dual responsive sites for tracking changes of lysosomal viscosity is presented. In-PHEM showed excellent fluorescence properties and high photostability. With this robust probe, the variation of the lysosomal viscosity in cells under different physiological conditions, including inducer stimulation, the process of starvation and apoptosis, was monitored using dual-channel imaging. Therefore, this work may provide a powerful tool for monitoring changes of lysosomal viscosity and helping to understand the relationship between the viscosity changes of lysosomes and their related diseases.