Diagnosis of Fatty Liver Disease by a Bright, Multiphoton-Active and Lipid-Droplet-Specific AIEgen with Nonaromatic Rotors

Fatty liver disease (FLD) has become an increasing global health risk. However, an accurate diagnosis of FLD at an early stage remains a great challenge due to lack of suitable imaging tools. To this end, we developed the first fluorescent two-photon aggregationinduced emission (AIE) luminogen ABCXF for high-contrast imaging of FLD tissue. ABCXF has a large Stokes shift, good two-photon absorption cross-section, bright red emission, high fluorescence quantum yield in solid state, and excellent photostability. It shows abnormal intramolecular charge transfer effect instead of twisted intramolecular charge transfer effect in polar solvents. Photophysical and crystal data demonstrated that it exhibits nonaromatic rotors - trifluoromethyto contribute to its AIE effect. Biocompatible lipid droplet-targeting ABCXF can selectively light up lesions in the FLD tissue with a high signal-to-noise ratio. It shows superior imaging performances compared to Oil Red O. Thus, ABCXF can be a powerful tool for the diagnosis and evaluation of FLD from a liver biopsy.