Triphenylamine-based fluorescent probes for lipid droplet detection and non-alcoholic fatty liver disease identification.

Lipid droplets (LDs) are important biomarkers for metabolic diseases such as non-alcoholic fatty liver disease (NAFLD), and they have significant research value in revealing the pathological mechanisms of these diseases. In this study, we designed three fluorescent probes based on triphenylamine, namely DM-1, DM-2, and DM-3, for the targeted detection of lipid droplets and the identification of NAFLD. DM1-3 exhibits a unique response to small polar environments and has high sensitivity, high selectivity, large Stokes shift, high fluorescence quantum yield, a wide pH range (2-8), and rapid recognition. Particularly, the fluorescence intensity of probe DM-1 at 576 nm (expressed in logarithmic form) has a good linear relationship with PBS/Diox (80-96 %) (R2 = 0.9888). Therefore, probe DM-1 was selected as the object for further study. The results of cell experiments indicated that the probe DM-1 could target lipid droplets within cells and exhibited low cytotoxicity. In vivo experiments successfully achieved the imaging of LDs in the liver of NAFLD mouse models at different stages. Together, these results demonstrated the potential of probe DM-1 as a polar-sensitive fluorescent tool for the early diagnosis and monitoring of NAFLD.