Studies Of Hydrogen Peroxide Fluorescent Probe Based On Phenyl Boronate Group

As the most important type of reactive oxygen species,hydrogen peroxide(H₂O₂)is not only related to cell proliferation,differentiation and migration,but also can effectively regulate the immune defense mechanism of human body.However,the abnormal level of hydrogen peroxide will disrup the oxidation-reduction balance of the biological system,which in turn leads to aging and many diseases.Therefore,it is extremely important to accurately and effectively detect H₂O₂ at the cellular level.Because the near-infrared fluorescent dyes are more suitable for imaging organisms because of their strong spectral tissue penetrating ability,little damage to organisms,and can overcome the background interference caused by cell systems.Therefore,real-time monitoring hydrogen peroxide molecules in living cells and organisms by fluorescent dye molecules has practical feasibility.Probes based on the oxidation of borate have attracted much attention because of their higher selectivity for H₂O₂ than other ROS.In this paper,dicyanomethylene-4H-pyran and its derivatives(DCM dye)are conjugated with benzene ring,quinoline and naphthalene ring to form a fluorophore,and phenyl boronic acid ester group is used as the H₂O₂ recognition group.Three H₂O₂reactive fluorescent probes(HA-NIR,DCM-C,NIR-DCM-HY)were synthesized.The optical performance and biological application of the three probes were evaluated by means of ultraviolet-visible absorption spectroscopy,fluorescence spectroscopy,and fluorescence imaging.Chapter 1:Summarize the physiological significance of hydrogen peroxide and research progress of fluorescent probes based on phenyl boronate group.Chapter 2:In this chapter,the benzene ring is conjugated with the DCM group to form a fluorescent group,and a highly specific,sensitive and fast response near infrared fluorescent probe HA-NIR is designed and synthesized for the detection of H₂O₂.The detection of H₂O₂ recognition by the probe in vitro by fluorescence spectroscopy shows that the in vitro selectivity of the probe to H₂O₂ is better than other interfering substances,and the fluorescence intensity has a good linear relationship with the concentration of H₂O₂,which can be used for H₂O₂.Qualitative and quantitative testing.At the same time,the probe HA-NIR was successfully applied to the endogenous and exogenous cells and the fluorescence imaging of H₂O₂in zebrafish,which can monitor cells and organisms in real time.Changes in H₂O₂levels in the body.Chapter 3:In this chapter,the larger quinoline ring of the conjugate system is conjugated with DCM to form a fluorescent group,and a new fluorescent probe DCM-C is designed and synthesized.The selectivity,detection limit,response time and other aspects of the probe are evaluated by fluorescence spectroscopy.The results show that the probe DCM-C has better selectivity to H₂O₂,and it has a lower detection limit(35.5 nm)and greater Stokes shift(187 nm)than the probe HA-NIR.At the same time,the probe was successfully used to monitor the changes of H₂O₂levels in cells and zebrafish through fluorescence imaging.Chapter 4:In this chapter,the naphthalene ring is connected to the DCM backbone,and a new type of near-infrared(NIR)fluorescent probe NIR-DCM-HY is synthesized for the detection of H₂O₂ inside and outside the cell.The results show that,compared with the probes in the previous two chapters,the Stokes shift of the probe NIR-DCM-HY is larger(203 nm)and the response time is shorter(14 min).At the same time,the probe also has the advantages of lower detection limit and good selectivity for H₂O₂,and the probe has been successfully used to monitor the changes of H₂O₂ levels in cells and zebrafish in real time.