Design And Synthesis Of Environment-Sensitive Small Molecule Probes And Imaging Study Of Pancreatic Cancer Cells

Cell microenvironment(viscosity,polarity,p H,etc.)play an important role in the regulation of cell biological activities.Cell growth,differentiation,apoptosis,autophagy and other biological activities cannot be separated from normal and stable cell microenvironment.However,the abnormal cell microenvironment parameters are often accompanied by the emergence of various diseases,such as inflammation,tumors,Alzheimer’s disease,atherosclerosis,etc.Similarly,the normal life activity of cells requires the cooperation between various organelles,and the physiological function of organelles also requires a normal and stable microenvironment.Therefore,it is meaningful to study the relationship between the change of organelle microenvironment parameters and the occurrence and development of diseases from the perspective of cell microenvironment.Pancreatic cancer is known as the "king of cancer".At present,its pathogenesis is not clear,and it is difficult to detect.The vast majority of patients with pancreatic cancer have been diagnosed at a terminal stage,and the window period for treating pancreatic cancer has been missed.Therefore,the early diagnosis of pancreatic cancer is an extremely important way to treat pancreatic cancer.The development of cancer is inevitably accompanied by changes in the cell microenvironment.Monitoring the changes of various cell microenvironment parameters to study the development process of pancreatic cancer and the pathogenesis of pancreatic cancer is of great significance for the early diagnosis of pancreatic cancer.To address the above problems,this paper has designed and developed four small molecule fluorescence probes targeting organelles,and conducted fluorescence imaging studies on pancreatic cancer cells from different cell microenvironments.1.Fluorescent probe targeting lipid droplets for monitoring changes in polarity(DCI-CZ).As the main storage place of neutral lipids in cells,lipid droplets are required to provide more energy for cell differentiation when cells become cancerous.Revealing the changes of lipid droplet polarity of pancreatic cancer cells is very important for studying the pathogenesis of pancreatic cancer.Therefore,we designed and developed a near infrared fluorescence probe(DCI-CZ)targeting lipid droplets to monitor lipid droplet polarity in pancreatic cancer cells.DCI-CZ has a large Stokes shift of close to 200 nm,which is a good indicator of polarity change under simulated physiological conditions.At the same time,we used the probe DCI-CZ to conduct fluorescence imaging studies on cells.DCI-CZ can target lipid droplets and distinguish the difference in lipid droplet polarity between pancreatic cancer cells and normal pancreatic cells.2.Fluorescent probe targeting lysosomes for monitoring changes in polarity(L-TCF-CZ).Lysosome is the reservoir of hydrolase in cells and plays a key role in the process of decomposing proteins,nucleic acids,polysaccharides and other biological macromolecules.At present,the study of lysosome polarity is still in the initial stage,and the study of lysosome polarity change during pancreatic cancer lesions is rarely reported,so monitoring the change of lysosome polarity is of great significance for the study of pancreatic cancer lesions.Based on this,we designed and synthesized a lysosome targeting near-infrared polarity probe(L-TCF-CZ)to monitor the change of lysosome polarity in pancreatic cancer cells.L-TCF-CZ can indicate the polarity change under simulated physiological conditions.At the same time,L-TCF-CZ can target lysosomes well and distinguish the difference of lysosomal polarity between pancreatic cancer cells and normal pancreatic cells in fluorescence imaging experiments.3.Fluorescence probe targeting mitochondria for monitoring changes in viscosity(MBODIHY).Mitochondria,as the "energy factory" of cells,provide power for various life activities,and the abnormal viscosity of mitochondria will inevitably affect the normal physiological function of mitochondria.At present,there is no probe for imaging the changes of mitochondrial viscosity in pancreatic cancer cells,so it is necessary to design and synthesize valuable fluorescent probes for imaging the mitochondrial viscosity in pancreatic cancer cells.So far,molecular rotorbased probes are still the mainstream tool for imaging viscosity.However,most of these probes have a "push-pull" structure and are often subject to polarity interference,which affects the probe’s detection of viscosity.Therefore,it is meaningful to develop a viscosity probe that can avoid the influence of polarity to conduct highly selective imaging studies on mitochondrial viscosity of pancreatic cancer cells.Based on this,we designed and synthesized a viscosity probe targeting mitochondria(M-BODIHY).Under simulated physiological conditions,M-BODIHY can indicate the change of viscosity well and avoid the interference of polarity well.At the same time,MBODIHY was able to target mitochondria and distinguish the difference in mitochondrial viscosity between pancreatic cancer cells and normal pancreatic cells in fluorescence imaging experiments.4.Mitochondrial and nuclear dual-targeting p H fluorescent probe(BZD-OH).The nucleus and mitochondria,as important organelles in the cell,play important roles in various life activities.How the p H of mitochondria and nucleus changes in the process of pancreatic cancer remains to be analyzed and studied.It is of great significance to explore the pathogenesis of pancreatic cancer to reveal the variation regularity of p H in pancreatic cancer cells.Therefore,we developed a case of Ph-sensitive probe(BZD-OH)for simultaneous bicolor imaging of mitochondria and nuclei.After testing,in the range of p H 4-9,BZD-OH can be a good indicator of p H change.Under acidic conditions,the maximum emission wavelength of the probe is about 570 nm,while under alkaline conditions,the maximum emission wavelength of the probe is about 660 nm,which provides the basis for the two-color imaging of different organelles.At the same time,in cell imaging experiments,BZD-OH can target both mitochondria and nucleus,green in the nucleus and red in the mitochondria.