Design And Synthesis Of Fluorescent Probes For Reactive Oxygen Species (ROS) And Their Application For Bioimaging

Oxygen(O₂)is essential for humans and other aerobic organisms.In the process of life,the human body produces a variety of oxygen-containing substances with high reactivity,collectively referred to as"reactive oxygen species(ROS)",including superoxide anions(O₂^·—),hydroxyl radicals(HO^·),and free peroxygen Base(ROO^·),hydrogen peroxide(H₂O₂),singlet oxygen(¹O₂)and hypochlorous acid/hypochlorite(HOCl/Cl O^—).ROS is mainly produced during aerobic respiration of mitochondria and participates in many physiological processes including signal transduction.At the same time,it is closely related to many diseases,such as neurological injury,inflammation,Alzheimer's disease,arteriosclerosis,and cancer.Wait.ROS at a normal physiological concentration helps the body maintain normal physiological processes.For example,hypochlorous acid is an important part of the body's immune system,which can destroy invasive bacteria and pathogens;hydrogen peroxide(H₂O₂)is involved in normal cell signal transduction O₂^·—has been identified as a potential messenger that regulates cell signals and participates in cell physiological processes;hydroxyl radicals(^·OH)are involved in the degradation of DNA,proteins,lipids and other biomolecules in cells and tissues;Singlet oxygen(¹O₂)plays a key role in photodynamic therapy(PDT).Although ROS are produced in the normal cellular environment and are very important to the living body,they are harmful to the body when they are excessively stimulated by external sources.Excessively generated ROS causes stress response through oxidizing biomolecules and induces cell death.Therefore,it is very important to detect the dynamic process of ROS in the body in real time.Among the various detection methods,the fluorescent probe method has the characteristics of visualization,sample non-destructiveness,high sensitivity,and high resolution.It has become an important tool for modern biological and medical research,and it is revealing the presence of biologically active molecules in cells and tissues.The positioning,concentration,and interaction of the drug and it play an increasingly prominent role in disease diagnosis and surgical operations.In the first chapter of the paper,the author summarized and reviewed various ROS probes developed by chemists in recent years,and made a general discussion on the properties of each probe.In the second chapter of the thesis,we introduced 9,10-dimethoxyanthracene(DMA)group on the basis of the"carbon-rhodamine"dye platform developed in the early stage of the research group,the probe MCR-DMA itself has no fluorescence.When it reacts with ¹O₂,the solution turns from colorless to pink,and the fluorescence increases significantly.The detection limit of the probe for ¹O₂ is 5.6?M,and the probe has achieved fluorescence imaging of exogenous ¹O₂ in Hela cells.In Chapter 3 of the paper,we designed and synthesized the NIR fluorescent probe NBod-H₂O₂ based on the PET mechanism.Through the study of the probe,we found that the probe showed good detection performance,including high sensitivity(detection limit of 0.05?M)and high selectivity to H₂O₂(compared to other biologically related species).In addition,the probe NBod-H₂O₂ has been successfully applied to the imaging of exogenous and stimulus-induced endogenous H₂O₂ in living cells and mice.