Synthesis And Properties Of Organelle Targeting Near-infrared Biothiol Fluorescent Probe Based On Benzopyran Salt

Biothiols,such as cysteine(Cys),homocysteine(Hcy)and glutathione(GSH)are very important biomolecules,which play irreplaceable roles in biological system.For example,biothiols are involved in regulating intracellular oxidative stress,signal transduction and maintaining normal cell growth and metabolism in biological systems.Some studies showed that abnormal levels of biomercaptan are associated with many diseases,such as leukopenia,psoriasis,liver damage and cancer.Therefore,it is more and more important to develop fluorescent probes that can detect biothiols sensitively and specifically.However,the emission wavelength of traditional fluorescent probes is usually less than 650 nm,which is easy to cause light damage and interference from cell self-fluorescence in biological applications.Therefore,near-infrared emission fluorescent probes that can reduce these negative effects are increasingly favored by researchers.Mitochondria,one of the most important organelles in eukaryotic cells,not only produce cellular energy,but also participate in many biological processes such as signal transmission,growth and death.In addition,damaged mitochondria are the major producers of reactive oxygen species,and biothiols have strong redox and nucleophilic properties,which are essential antioxidants to protect cells and tissues from endogenous ROS and free radical oxidation.Therefore,the detection of biothiols in mitochondria is very helpful for clinic pathological diagnosis.In conclusion,it is valuable to develop biothiol fluorescent probes with near-infrared and mitochondria-targeting.In this study,we designed and synthesized three biothiol fluorescent probes based on benzopyran salt with the function of mitochondria-targeting and near-infrared emission.Among them,LAA could recognize Cys exclusively;LAD could simultaneously detect Cys,Hcy and GSH,and LA-O-NBD could distinguish Cys/Hcy and GSH with dual-channel.The main research contents are as follows:In chapter 1,the structure and the importance of biomercaptan,the recognition mechanism of fluorescent probes,the progress of fluorescent probes with organelle targeting and biothiol recognition properties were discussed.In chapter 2,the near infrared fluorescent probe LAA was designed and synthesized with benzopyran salt as fluorophore and acrylate as recognition group,and a series of studies were conducted on the recognition performance of the probe LAA to Cys.The results indicated that the probe LAA can recognize Cys sensitively and specifically.In addition,the presence of other analyses did not interfere with the detection of Cys by probe LAA.Cell experiments showed that the probe LAA could be used for imaging living cells.Co-localization experiments showed that the probe LAA could locate mitochondria.In chapter 3,the near-infrared fluorescent probe LAD was designed and synthesized using benzopyran salt as fluorophore and 2,4-dinitrobenzene sulfonate as recognition group.The recognition performance of LAD to biothiol Cys/Hcy/GSH was studied.The results showed that LAD could detect biomercaptan sensitively and specifically.In addition,the presence of other analyses did not interfere with the detection of biomercaptan by the LAD probe.Cell experiments showed that LAD could be used for imaging living cells.Co-localization experiments showed that the probe LAD had the ability of mitochondria-targeting.In chapter 4,the near-infrared fluorescent probe LA-O-NBD was designed and synthesized with benzopyran salt as fluorophore and NBD as recognition group,and the recognition performance of the probe LA-O-NBD to biothiol Cys/Hcy/GSH was studied.The results showed that the probe LA-O-NBD could recognize and distinguish biothiol Cys/Hcy and GSH with dual-channel.In addition,the presence of other analyses did not interfere with the identification of biothiols by the probe LA-O-NBD.Cell experiments showed that the probe LA-O-NBD could be used for living cell imaging.The co-localization experiment showed that the probe LA-O-NBD could locate mitochondria.