Study On Plasma Membrane-and Lysosome-targeted Carbazole-based Two-photon Fluorescent Probes For Visualization Of Apoptosis

As the most common mode of programmed cell death,apoptosis regulates cell homeostasis and maintains cell homeostasis.The characteristic changes of apoptosis include morphological changes,asymmetry of cell membrane and loss of integrity.Lysosome is an important suborganelle in cells,and more and more evidence shows that it participates in apoptosis.Abnormal changes in lysosome polarity,viscosity and p H may cause serious dysfunction,such as apoptosis and autophagy.The cell membrane is the protective boundary of the cell.It is essential for maintaining cell integrity and is closely related to cell growth and death.Abnormal cell apoptosis can cause cancer,Alzheimer's disease,myocardial infarction and other diseases.Therefore,the real-time continuous monitoring of cell apoptosis has great potential value for the early diagnosis of cancer and other diseases,the evaluation of therapeutic effect and the screening of apoptosis-related drugs.Organic small molecule fluorescence probe combined with confocal fluorescence imaging technology can carry out fluorescence imaging on living cells,tissues and in vivo,and present the analysis results intuitively and efficiently to provide key target indicators for the diagnosis and treatment of cancer and other diseases.Photodynamic therapy(PDT)is a new technology for the treatment of cancer,tumor and other diseases.Reactive oxygen species produced by photodynamic force can oxidize suborganelles and intracellular biomacromolecules,etc.,causing cell damage and thereby inducing apoptosis or necrosis of tumor cells.Combined with two-photon confocal imaging,the photodynamic therapy process can be observed in real time.Based on the above research background,a two-photon fluorescent probe CMC targeting cell membrane and a two-photon fluorescent probe CP responding to the polarity of lysosomes were designed and synthesized in this study.In the structural design of probe CMC,the specific location of cell membrane with amphiphilic probe CMC was designed.CMC has good photophysical properties,biocompatibility and excellent photostability in living cells.Under light irradiation,CMC can effectively induce ROS production,leading to cell apoptosis/necrosis.Two-photon confocal imaging can be used to observe apoptosis induced by CMC and the process of photodynamic therapy in real time.These findings on the production of reactive oxygen species are expected to spark new research into photodynamic therapy and efforts to create new drugs to treat cancer.The probe CP has a good fluorescence response to the polarity of the solvent and can detect the polarity of the solution.CP has excellent two-photon properties,and its fluorescence lifetime and fluorescence quantum yield are linearly related to the polarity.CP can effectively locate the lysosome and conduct fluorescence imaging study on the real-time change of lysosome polarity in the process of apoptosis.This will provide a new method and idea for diagnosis of apoptosis-related diseases,screening of apoptosis-related drugs and evaluation of their therapeutic effects.