Construction of a mitochondria-targeted fluorescent probe for the detection of viscosity in living cells and zebrafish

Abstract

Mitochondria are key organelles for cellular energy metabolism and signaling regulation, and their internal environment is critical for maintaining cellular function. Recent studies have shown that viscosity changes in the mitochondrial microenvironment are inextricably linked to the occurrence of inflammatory responses in organisms. Therefore, the development of a fluorescent probe capable of monitoring mitochondrial viscosity changes in real-time holds great promise for facilitating disease prevention, diagnosis and treatment. In this study, we used a simple organic synthesis method to construct a novel small molecule fluorescent probe, PMI-MT, based on the twisted intramolecular charge transfer (TICT) mechanism and capable of detecting viscosity changes in cells and zebrafish. PMI-MT demonstrates high sensitivity to viscosity and is photostable, biocompatible and minimally intrusive, and exhibits strong mitochondrial targeting ability. Experimental results demonstrated a significant 53-fold increase in fluorescence intensity when PMI-MT was dissolved in glycerol compared to methanol. Meanwhile, PMI-MT was able to detect viscosity changes in cells and zebrafish. More importantly, it has also been successfully used to monitor viscosity changes in inflammatory zebrafish in vivo. The results of this study indicate that PMI-MT has the potential to not only monitor mitochondrial viscosity changes, but also to be utilised for the early diagnosis and treatment of inflammation-related diseases.