A triphenylamine-based fluorescent probe with large Stokes shift for wash-free imaging of lipid droplets and diagnosis of fatty liver

Abstract

As a dynamic organelle, lipid droplets (LDs) are intricately involved in lipid storage, metabolism and various life processes. Their aberrant behaviour commonly signifies cellular dysfunction, which may contribute to the occurrence of a variety of diseases, particularly non-alcoholic fatty liver disease (NAFLD). Thus, it holds immense medical significance to develop specific probes targeting LDs to monitor the changes in the development of NAFLD. To this end, a D–π–A structural probe TSB was synthesized by Knoevenagel reaction based on triphenylamine and β-diketone boron difluoride. Optical studies revealed that probe TSB exhibited a strong solvation effect and a large Stokes shift (up to 299 nm in acetonitrile solution). Moreover, wash-free and co-localization experiments demonstrated the probe's precise targeting of LD sites within cells through a washing-free procedure with extreme specificity. Importantly, TSB has been validated for distinguishing between fatty liver and normal liver at the organ level, thereby holding potential for early diagnosis of NAFLD. These experimental findings will lay a theoretical foundation for the design and synthesis of more superior fluorescent probes specifically targeting LDs.