Synthesis And Application Of Two Nuclear DNA Targeting Fluorescent Dyes

In this thesis,two DNA-targeted fluorescent indicators,HoeSR and HoeSR-1,were designed and synthesized.The application of two probes in studying the microstructure and function of the nucleus was investigated by spectral test and fluorescence imaging.HoeSR and HoeSR-1 are formed by Hoechst covalently linking with different sulforhodamine by "click reaction",wherein Hoechst has DNA minor groove targeting,and amidated modified sulforhodamine has good fluorescence properties and pH sensitivity.Studies have shown that two indicators can be specifically localized to living cell DNA,and have a low staining background,which can display and detect the microscopic structure and microenvironment of living cells.Among them,HoeSR has the property of sparse luminescence after binding to DNA;it can be used for super-resolution imaging of nuclear DNA,revealing the fine structure characteristics of nuclear DNA in mitosis.HoeSR-1 has a double fluorescence emission peak with a sensitive ratio value in the range of pH = 6.00 ~ 9.00.That means that HoeSR-1 is suitable for the study of pH in the nucleus.This work utilized the ratio value gained by the fixed HeLa cells stained with HoeSR-1 at different pH values vs the ratio value of intact cells stained with HoeSR-1 to obtain the pH value of normal cells nucleus.And finally,the pH value of intact HeLa nucleus was pointed out in the range of pH = 8.50 ~ 9.00.The two fluorescent indicators designed in this thesis have strong practicability and provide an important tool for studying the nuclear structure and physiological environment of nuclear DNA.