A Multifunctional Single-Molecule Fluorescent Probe for Imaging Dual-Organelle and Identification of Liver Injury...

Lipid droplets (LDs) and mitochondria, respectively, play important roles in the body as energy storage banks and supply stations. Therefore, visualizing anomalous changes in both using an effective dual-targeting tool is of profound importance for a comprehensive understanding of the mechanism of occurrence of related diseases. Here, we constructed 11 kinds of fluorescent probes (PTPCs) of C_1-10 and C₁₂-alkyl chains using phenothiazine, which has excellent luminescence properties, as the skeleton, based on side chain strategies with different carbon atom numbers. All probes displayed excellent responsiveness to viscosity. Bioimaging showed that all probes (except for PTPC12, the longest chain length) were all anchored to mitochondria. Interestingly, molecules containing C₄-C₉ can stain LDs and mitochondria separately in the dual emission channel. Moreover, the mitochondrial imaging effect of PTPC4 was not affected by the fluctuation of mitochondrial membrane potential (MMP). Not only that, the viscosity sensitivity of PTPC4 enabled the visualization of abnormal changes in viscosity levels in a variety of cellular models, and it can even easily distinguish between normal liver and liver-damaged liver. Furthermore, by utilizing the dual-color imaging function of PTPC4, the general pattern characterized by LDs accumulation during mitochondrial dysfunction was successfully revealed. More commendably, probe PTPC4 has demonstrated great potential in detecting normal liver and nonalcoholic fatty liver at organ level in mice. PTPC4 serving as a two-color organelle imaging tool, has proven advantageous for in-depth investigations into LDs and mitochondria-related diseases. This has positively contributed to the advancement of diagnostic and therapeutic strategies.