Silicon Rhodamine-Based Fluorescence Lifetime Probe for Dynamics Mapping Lysosomal Oxidative Stress

Lysosomes are organelles responsible for cellular degradation and recycling. The detection of changes in the lysosomal microenvironment, such as viscosity, oxidative stress, and pH value, as well as their interactions among dynamic organelles, remains an intriguing field that contributes to elucidating intracellular homeostasis. Here, we describe the development of a fluorescent probe tool for uniting fluorescence lifetime imaging microscopy (FLIM) and dual-channel near-infrared (NIR) fluorescence signals, which can simultaneously monitor viscosity and reactive oxygen species (ROS) in lysosomes. SiR-Eda exhibits a viscosity-dependent fluorescence lifetime and ROS-sensitive fluorescence emission, allowing for real-time tracking of lysosomal oxidative stress and viscosity within living cells. We demonstrate the utility of SiR-Eda in detecting changes in lysosomal viscosity and ROS in response to various stimuli including oxidative stress and lysosomal dysfunction. Our probe provides a convenient wash-free multifunctional tool for investigating lysosomal biology and has potential applications in the diagnosis and treatment of lysosome-related diseases.