| The proposal of Aggregation-Induced Emission（AIE）has had a significant impact on the field of organic photofunctional materials.AIE Luminogens（AIEgens）have played an irreplaceable role as a low-cost and excellent luminescent probe in aqueous solution for monitoring biological processes,organelle labeling and cancer cell ablation,among which the labeling of specific organelles using AIEgens is of great importance.Important organelles such as mitochondria,lysosomes and lipid droplets in eukaryotes are the main targets of AIEgens-specific staining,and visual monitoring of relevant organelles shows great potential for early diagnosis and treatment of the development of relevant diseases.Our work focus on the synthesis and properties of lipid droplet-targeted fluorescent probes with AIE effects and cellular imaging are as follows:In chapter 2,three AIE lipid droplet fluorescent probes based on naphthalimide scaffold,TPA-NDI-1,TPA-NDI-2 and TPA-NDI-3,were synthesized.The three compounds showed a sensitive fluorescence response to solvent polarity,such as,it emitted greenish-yellow fluorescence in toluene and red fluorescence in methylene chloride.At the same time,they all had AIE effects in a mixed solution（DMSO/H2O）,all these features enabled them to produce a two-color fluorescence response to organelle polarity in aqueous solutions.In addition,the three probes showed excellent p H stability,kinetic stability,low cytotoxicity,and large Stokes shift,and all of them were able to specifically locate intracellular lipid droplets for fluorescence imaging of intracellular lipid droplets.In chapter 3,a fluorescent probe TPE-LD-Mor with AIE effect that could target both lipid droplets and lysosomes was developed.In addition,morpholine was replaced by pyridine group,thus a structurally similar comparison probe TPE-LD-Py was synthesized.The two compounds not only exhibited AIE effects in THF/H2O mixtures,but also produced regular fluorescence responses to the solvent polarity and solution viscosity.Besides,the two compounds showed excellent p H stability,kinetic stability,anti-interference ability,and large Stokes shift,indicating that both of them have the potential to be used in cells.In addition,the two compounds introduced different targeting groups could produce different organelle localization capabilities,which provides a reference for the design of intracellular multifunctional fluorescent probes. |
