Study On Synthesis And Application Of Small Molecule Biothiol Fluorescent Probe Based On Chalcone Dyes

Small molecular biological thiols,such as cysteine(Cys),homocysteine(Hcy),glutathione(GSH),play an important role in the physiological process of human beings.They participate in many biological processes and are indispensable parts in maintaining the physiological activities of living organisms.In recent years,the detection of biothiols has become an active research area due to the biological importance of small molecule biological thiols.Among the many methods for detecting thiols,the fluorescent probe method are favored by researchers.It is simple,sensitive,selective and applicable to the detection of intracellular biothiols,and has been widely used.However,because the structures and chemical properties of the three important small-molecule biothiols,Cys,Hcy,and GSH,are relatively similar,they are difficult to distinguish,which becames a huge challenge.The lysosome was an important acidic organelle(pH=4.4?5.5),containing about 50 different degrading enzymes.Biothiols promoted proteolysis in lysosomes by reducing disulfide bonds.Since biological thiols played an important role in lysosomes,it was of great significance to effectively identify and detect biological thiols in lysosomes.In summary,the development of fluorescent probes capable of distinguishing and detecting biological thiols and lysosome-targeted fluorescent probes for identifying biological thiols had far-reaching significance.In this paper,based on chalcone dye,three fluorescent probes for the detection of bioscaptols has been designed and synthesized.Among them,two fluorescent probes for the specific detection of Cys targeting lysosomes were designed,and the other fluorescent probe for the simultaneous detection of Cys,Hcy and GSH was designed as follows:In Chapter 1,the importance and detection methods of bioscaptan,the composition and recognition mechanism of bioscaptan fluorescent probe,the research progress of bioscaptan fluorescent probe and the structure,properties and applications of chalcone dye were briefly described.In Chapter 2,a fluorescent probe 1 was synthesized using chalcone dye as fluorophore,chloropropionate as recognition group and morpholine as lysosomal locator.The ultraviolet and fluorescent properties of the probe 1 on Cys were measured.The results proved that probe 1 could specificly identify Cys from other amino acids.In addition,probe 1 was successfully used for Cys imaging in living cells,and it was proved that probe 1 had the ability to target lysosomes.In Chapter 3,a fluorescent probe 2 for the specific detection of Cys was synthesized using chalcone dye as fluorophore,acrylate as recognition group and morpholine as lysosomal locator group.The properties of probe 2 for the recognition of Cys were studied.The results showed that probe 2 could specificly recognize Cys from other amino acids.In addition,the cell co-localization experiment showed that probe 2 can target lysosomes with a lysosome localization function;In Chapter 4,using chalcone dye as the fluorophore and 2,4-dinitrobenzenesulfonate as the recognition group,a fluorescent probe 3 for simultaneous detection of GSH,Cys and Hcy was synthesized,and the probe 3 was studied to identify the relevant properties of GSH,Cys,and Hcy.When probe 3 was excited by an excitation wavelength of 410 nm,in the presence of GSH,Cys,and Hcy,it exhibited a clear fluorescence emission peak at 569 nm,releasing SO₂ gas and yellow fluorescence.It could be seen that probe 3 could simultaneously detect and recognize GSH,Cys and Hcy in amino acids,indicating that probe 3 had a strong selectivity for GSH,Cys and Hcy.