Rational Design of a Near-Infrared Ratiometric Probe with a Large Stokes Shift: Visualization of Polarity Abnormalities in Non-Alcoholic Fatty Liver Model Mice.

Tracking liver polarity with noninvasive and dynamic imaging techniques is helpful to better understand the non-alcoholic fatty liver (NAFL). Herein, a novel near-infrared (NIR) fluorescent probe Cy-Mp is constructed using a "symmetry collapse" strategy. The structure modification leads to the conversion of locally excited state fluorescence to charge transfer state fluorescence. Cy-Mp emits at near-infrared (NIR) wavelengths with high photostability as well as a large Stokes shift. Cy-Mp exhibits a ratiometric response to polarity, providing more accurate analysis of intracellular polarity via the built-in internal reference correction. Most importantly, the in vivo studies indicate that Cy-Mp can accumulate in the liver and the decreased polarity in the liver of mice with NAFL is verified by the ratiometric imaging, implying the great potential of Cy-Mp in the diagnosis of NAFL.