Design,Synthesis And Application Of Novel Fluorescent Probes For Reactive Oxygen Species

Reactive oxygen species(ROS)are highly active substances commonly found in organisms,which can maintain the dynamic balance of intracellular redox and homeostasis,as well as play an important role in cell signal transmission and cellular immunity.HOCl and ONOO~-participate in a variety of physiological processes in vivo as important active substances.However,when the concentration of HOCl and ONOO~-is deviated from the normal physiological level,it will cause oxidative damage to proteins and other macromolecules that resulted in oxidative stress and further lead to various diseases.Small molecule fluorescent probe is an ideal method for in vivo molecular imaging because of its high reaction specificity,good biocompatibility and good spatio-temporal resolution.In this paper,two kinds of fluorescent probes with different strategies were designed and synthesized to detect HOCl and ONOO~-,and applied to the study of intracellular fluorescence imaging.This paper mainly includes the following contents:The first chapter describes the research background,the common luminescence mechanism of fluorescent probes,the research progress of reactive oxygen fluorescent probes,and introduces the significance of the topic and the research content of this paper.In chapter 2,an AND logic gate based fluorescent probe LG-3 was designed and synthesized for the detection of HOCl and ONOO~-.LG-1 and LG-2 were synthesized by connecting 1,3-oxathiolane and borate ester groups as the recognition groups of HOCl and ONOO~-respectively.The properties of the recognition groups were measured by the spectral test results of LG-1 and LG-2 with HOCl and ONOO~-,and then LG-3 was tested with HOCl and ONOO~-.The experimental results show that LG-3 can stably exist in physiological buffer solution,and emitted strong fluorescence only in the presence of HOCl and ONOO~-,as well as exhibited high sensitivity toward HOCl and ONOO~-,with detection limits of 22nM and18.8nM,respectively.In the presence of other interfering substances such as reactive oxygen species,reactive sulfur species or ions,LG-3 exhibited a high specificity for HOCl and ONOO~-.In addition,LG-3 demonstrated the ability to simultaneously detect HOCl and ONOO~-in mouse macrophages.In chapter 3,a fluorescent probe DQ-HOCl based on dual-quenching strategy was designed and synthesized for the detection of HOCl.The probe used 6-methylamino-2-naphthalaldehyde as the fluorescence group,and p-hydroxyaniline and 1,3-thiazopentyl was connected to the both ends of the fluorescence group as the HOCl recognition groups respectively as well as quenching the fluorescence of fluorophore via ICT and PET process that greatly reduced the fluorescence background of the probe.After rapidly reacting with HOCl(within 1min),the probe DQ-HOCl showed the 8000 times fluorescence enhancement and the low detection limit(3.5nM)to HOCl,and the probe was not affected by other interfering substances.In addition,cell experiments showed that the probe DQ-HOCl had the ability to recognize both exogenous and endogenous HOCl.