Design,Synthesis And Characterization Of Fluorescent Probes Response To Reactive Oxygeb Species

Reactive oxygen species(ROS)can mediate a variety of physiological active reactions,such as singlet oxygen(¹O₂)and lipid(LH)peroxidation products.Under normal physiological conditions,antioxidant enzymes combine with endogenous and exogenous antioxidants so that ROS are broken down to very low and beneficial levels.However,when ROS exceeds a certain concentration range,biological molecules will be damaged.Under aging,stress and some pathological conditions,the production of ROS increases or the clearance ability decreases,and the morphology and function of tissue cells are destroyed.Excessive ROS can cause or aggravate a lot of diseases and accelerate the aging process of human body.Therefore,it is of great significance to detect the changes of redox state of cells accurately in real time.However,traditional methods are difficult to achieve high sensitivity,high selectivity and real-time detection.Therefore,the study of novel fluorescent probes with high selectivity and sensitivity is of great theoretical significance and application value.Among ROS,hydrogen peroxide is a mild oxidant,while it can be converted into other strong oxidants in living organisms;Hypochlorite or hypochlorite ion often exists in tap water and is a strong oxidant.These two ROS(H₂O₂/Cl O^?)can react with many biomacromolecules to cause dysfunction of the body,leading to diseases such as neurodegenerative diseases,cardiovascular diseases and osteoarthritis.In this work,three types of small molecule fluorescent probes were designed and synthesized for ROS detection and live cell imaging.The fluorescence probe molecule itself has only a weak fluorescence.After the probe reacting with the substance,the fluorescence of the probe is enhanced by the release of the fluorescent group.It achieves the purpose of real-time monitoring through fluorescent switch.The synthesis method of different fluorescent probes was studied.The target probe was confirmed by ¹H NMR,¹³C NMR,HRMS and MFS.The anti-interference performance,fluorescence release process and detection limit of the probe were also explored through experiments in vitro.The results showed that all three probes were specific and had a good linear relationship over a range of concentrations with detection limits of 0.1?M,46 n M and 65 n M,respectively.In addition,after a few minutes of reaction of the probe L5 with hydrogen peroxide,the fluorescence intensity of the system is rapidly enhanced(Turn-on,up to 1200 times)and the properties are excellent.Probes toxicity was measured by MTT method in LO2 and HeLa cells.The results showed that all three probes were low toxicity.In addition,the stability of the probe in the presence of different p H and interferences was also investigated.The results show that the probe has strong anti-interference ability and good stability under the research conditions.Probes were used to detect ROS in HepG2 and HeLa cells and to study their imaging characteristics.Three probes can achieve cell level imaging.Hydrogen peroxide probe based Cyanine was also applied to zebrafish in vivo.Endogenous hydrogen peroxide was generated by using a drug damage model,and then the probe was used for imaging research.The results show that the probe Cy-H₂O₂ can image the location of"Paracetamol"damage(hydrogen peroxide production)and can also distinguish the difference in imaging locations of endogenous and exogenous hydrogen peroxide.This research provides a new method for disease detection research and has important theoretical significance.