Quantification of lipid droplets polarity for evaluating non-alcoholic fatty liver disease via fluorescence lifetime imaging

Lipid droplets (LDs) are a kind of subcellular organelle, and LDs' polarity is closely associated with the initiation and development of non-alcoholic fatty liver disease (NAFLD). However, due to the lack of robust tools, the evaluation of NAFLD faces the challenge of quantitative diagnosis. Herein, we synthesized a new polaritysensitive probe CCB, enabling it to quantify the process of fatty liver degeneration in real-time via fluorescence lifetime imaging microscopy (FLIM). The fluorescence lifetime of the probe CCB had a good linear fitting relationship with the polarity, which could be used to quantitatively detect the LDs' polarity via fluorescence lifetime. The robust probe CCB successfully monitored the changes in LDs' polarity via FLIM at cellular and tissue levels in the steatosis process of NAFLD for the first time, which may enlighten to the quantitative diagnosis of NAFLD.