Aggregation-induced Emission Molecules For Fluorescent Detection Of ONOO~- And Imaging Of Lipid Droplet

Fluorescent probes are effective tools for detecting molecules and imaging in biological systems due to their simplicity,sensitivity,visualization,real-time analysis and non-invasiveness.However,traditional fluorescent probes are greatly limited in detection and imaging due to the effects of aggregation-caused quenching(ACQ)of fluorescence.Recently,fluorescent probes with aggregation-induced emission(AIE)feature have attracted much attention because they can effectively avoid the adverse effects of ACQ.Based on the unique properties of AIE,in this dissertation,several fluorescent molecules have been synthesized for fluorescent detection of peroxynitrite and imaging of lipid droplet.The main contents are as follows:1.Peroxynitrite(ONOO~-)is one of the reactive nitrogen species(RNS)molecules in living organisms,which plays an important role in cells,such as signal transduction and regulation of apoptosis.Excessive ONOO~-may also cause a variety of diseases.Therefore,a ratiometric fluorescent probe BTCV-ONOO with AIE properties was designed and synthesized for detection and imaging of ONOO~-.BTCV-ONOO is weakly emissive in aqueous solution.While after adding ONOO~-,the fluorescence intensity of the probe decreases at 632 nm,and increases at 525 nm.This ratiometric response mode can effectively reduce interferences from microenvironment changes around the instrument,and photobleaching.In addition,the probe exhibited high selectivity toward ONOO~-.BTCV-ONOO also displayed high stability in a wide pH range.Moreover,fluorescence imaging of endogenous and exogenous ONOO~-in live cells and live mice was also realized,demonstrating that BTCV-ONOO provides an easy-to-handle tool for the tracking of physiological functions of ONOO~-both in vitro and in vivo.2.Lipid droplets(LDs)are important organelles in the cells.It is involved in mediating lipid metabolism and storage,membrane transfer,protein degradation and signal transduction.Abnormalities in LDs may also cause a variety of metabolic diseases.Based on this,two nearinfrared fluorescent molecules CFM-TPE and BCI-TPE with AIE properties were designed and synthesized for lipid droplet-targeted imaging.Photoluminescence properties have shown that the emission wavelengths of CFM-TPE and BCI-TPE are in the near-infrared region,which can effectively reduce the interference of cell background fluorescence and photobleaching,and penetrate deeper into cells.In addition,CFM-TPE exhibited a large Stokes shift and can selectively target lipid droplets.The probe CFM-TPE offers great opportunity for visualization of lipid droplet related physiological process and the development of metabolic diseases related to lipid droplets.