Design,Synthesis And Application Of Fluorescence Probe For Detection Of HSA And Cys

This thesis deals with two parts of work.Part 1 is the design,synthesis and application of a highly selective and sensitive fluorescent probe for monitoring HSA.Part 2 is the design,synthesis and application of a highly selective and sensitive fluorescent probe to detect Cys.1.HSA(Human Serum Albumin)is the most abundant content in human blood plasma,serving as biological macromolecules with important physiological function It contains 580-585 amino acid residues with a molecular weight of 60 kDa and a biological half-life of about 20 days.It is able to transport endogenous substances and different series of exogenous drugs as while hence it plays a key role in the kinetics and efficiency of drugs.Clinically used for the symptomatic treatment of major bleeding,shock,burns,erythrocyte cytosis,and hypoalbuminemia.HSA has also been applied to model proteins in clinical research and has long attracted the enthusiasm and interest of researchers.Therefore,it has important research and application value in biological science,molecular biology,clinical medicine and other fields.Small molecule fluorescent probes have attracted the attention to researchers and have been widely used in the field of biological active substance detection because of their high sensitivity,high selectivity,and simple operation.Although fluorescence analysis method is widely applied to explore the interaction between small molecules and proteins,the sensitive detection of HSA by fluorescent probes is still rare.In addition,there are still some limitations of reported fluorescent probes,such as limited selectivity or insufficient sensitivity to detect microcrystalline HSA in the sample.What's more,the complex and flexible binding site of HSA and the characteristics of HSA itself hinder the researchers to a large extent in-depth study.In the second chapter of this thesis,we introduce a fluorescent probe XYQ-1 based on quinoline rings and indole rings for the detection of HSA.The probe enhances its fluorescence by changing the microenvironment,via specifically acted on site 1 of HSA.The fluorescence intensity showed a good linear relationship with the HSA concentration in the range of 0-0.2 g/L(R2=0.9924).Compared with other amino acids or biomolecules,XYQ-1 exhibits excellent properties of selectivity and anti-interference to HSA,and even discriminates HSA from BSA.Furthermore,we successfully applied XYQ-1 to the detection of HSA in real urine samples and in 293T cells.2.Cys(Cysteine)is an amino acid with a thiol group that participates in the reduction of cells in the body and the synthesis of proteins and glutathione.It has the function of protecting cells from poison damage.Elevated levels of Cys in serum are associated with neurotoxicity,rheumatoid arthritis,Parkinson's disease,Alzheimer's disease,and coronary heart disease.Lack of Cys can also lead to liver damage,hair loss,edema,growth retardation,and loss of muscle fat.Cys is involved in a variety o f physiological and pathological functions,and its functional mechanism and signal pathways have received extensive attention.The methods of monitoring Cys in vivo have become important topics.The third chapter describes a BF2 derived fluorescent probe XYQ-2 for detection of Cys.In this probe,azide groups were introduced into the molecule to detect Cys,via the reaction of Cys with azide group.XYQ-2 exhibits excellent selectivity and sensitivity to Cys compared to other common amino acids or reducing substance.The fluorescence intensity was enhanced by more than 60-fold in the presence of Cys,and the fluorescence intensity showed a good linear relationship with Cys concentration in the range of 1-5 eq(R2=0.9976).The maximum excitation and emission wavelengths of the probes were 395 nm and 510 nm respectively,with a Stokes shift of 115 nm.Besides,we successfully applied XYQ-2 to the detection of Cys in Hep G2 cells.