Synthesis And Properties Of A Novel Viscosity Fluorescent Probe

Intracellular viscosity is an important parameter in the cellular microenvironment,which can reflect the diffusion rate of material between cells,thus reflecting the expression of biological behavior and the generation of disease.Fluorescence imaging technology has been widely studied in recent years.It has the advantages of high sensitivity,low cost and high spatial and temporal resolution,so it can realize the detection of intracellular viscosity changes.In this thesis,three small molecular viscosity probes were designed and synthesized to detect intracellular viscosity changes.Mitochondria are semi-autonomous cytoplasmic organelles in cells whose matrix contains enzymes and proteins.Their diffusion rate is impeded by the mitochondrial crest,making them the more "crowded" in a cell.Mitochondrial dysfunction will affect the composition of the matrix,and further influence the viscosity of the mitochondria.Therefore,detecting the change of mitochondrial viscosity to observe the status of mitochondria is very beneficial to the diagnosis and treatment of diseases.We designed and synthesized a viscosity probe ZS1 with mitochondrial targeting.The probe exhibited a very good response to viscosity changes and possessed a large Stokes shift,reaching 180 nm in methanol and 170 nm in glycerol.The probe ZS1 has been successfully used to detect viscosity changes in mitochondria of cells.Cyanine as an excellent small molecule fluorescent dye,compared with other dyes,has the advantages of high photostability,long absorption and emission wavelength.Probe ZF1 used cyanine as a platform to study the fluorescence probe and cell imaging.Compared with ZS1,the probe ZF1 had a longer near-infrared emission wavelength.ZF1 had large Stokes shift(126 nm in methanol,148 nm in glycerol).With the increase of viscosity,the near-infrared fluorescence emission of the probe increased significantly.The probe ZF1 had also been successfully used for imaging changes in cell viscosity.Fluorescent probes with aggregation induced emission(AIE)can often alleviate the problem that traditional dyes cannot be effectively detected at high concentrations.We designed and synthesized a viscosity fluorescent probe ZL1 with AIE effect by using the triphenylamine part of probe ZS1 and the imidazole part of probe ZF1.The probe not only showed a good AIE effect,but also had a large Stokes shift(up to 154 nm in methanol,125 nm in glycerol).Moreover,the probe ZL1 had been successfully used to monitor changes in intracellular viscosity.