Three polarity-sensitive fluorescence probe possessing AIE activity and its application on lipid droplets imaging

As a neutral lipid storage organelle, lipid droplets play fundamental roles in cell metabolism and growth. In this study, we developed three fluorescent probe targeting lipid droplets with D-A type structures based on naphthalimido derivatives, which were named as TPA-NDI-1, TPA-NDI-2 and TPA-NDI-3. Interestingly, the three compounds exhibited polarity-sensitive properties which emitted greenyellow fluorescence in toluene and red fluorescence in dichloromethane. Meanwhile, they all possessed AIE effect in mixed solution of DMSO/H2O, which were suitable to intracellular lipid droplets imaging. Moreover, the three probes exhibited excellent pH and kinetic stability, low biotoxicity and large Stokes shift. All these properties suggest that the three compounds can be used as potential probes for lipid droplets visualized detection.