Design,Synthesis And Multi-sensory Of Fluorescent Probes For Biothiols And H₂S

Fluorescent probes are generally composed of small organic molecules with large conjugated and coplanar structures.They have attracted increasing attentions and become one of the most active research fields in resent years because of their advantages,such as low cost,easy synthesis,separation and purification,high selectivity,high sensitivity and biocompatibility.There is a significant correlation between biothiols(cysteine,Cys;homocysteine,Hcy;glutathione.GSH)and hydrogen sulfide(H2S)in the living systems.The four compounds play important roles in many physiological processes and disease diagnosis?In this paper,three types of fluorescent probes were designed and prepared.The different reactions of Cys,Hcy,GSH and H2S with probes lead to different products with different photophysical properties,which enabling the high selectivities and high sensitivities.Thus,these probes could be applied in intracellular fluorescence imaging.The main contents and results are focused as following:1.The design strategies,sensing principles are introduced.The latest research progresses of fluorescent probes sensing biothiols and H2S are reviewed.2.A novel fluorescent Probe 1 based on acridine orange was developed for the selective detection of biothiols.This probe shows emission-dependent selectivity for GSH over Cys/Hcy and pH-dependent selectivity for Cys over Hcy/GSH.Probe 1 displays high selectivity for GSH in the EtOH-PBS(pH=7.4.1%EtOH)solution,and the detect limit of the fluorescent assay for GSH is as low as 5.0 nM in a rapid response of 2 min.Meanwhile,Probe 1 displays high selectivity for Cys in the EtOH-PBS(pH=6.0,20%EtOH)solution,and the detect limit of the fluorescent assay for Cys is 0.11?M in a rapid response of 8 min.In addition,spectral data of the control compounds and MALDI-TOF MS datas confirmed the sensing mechanism of Probe 1 for biothiols.Finally,Probe 1 could be used to separately sense intracellular GSH and Cys.3.A coumarin-based fluorescent Probe 2 having a 3,4-dimethoxythiophenol leaving group was developed for the selective detection of biothiols and H2S.The different sites could react with biothiols or H2S in different mechanisms and lead to different products with distinct photophysical properties.It could thus be used to separately sense the four compounds and selectively detect Cys,GSH and H2S.The detect limit of the fluorescent assay for Cys,GSH and H2S were 31.4 nM,9.7 nM and 0.11?M,respectively.In addition,spectral data of the control compounds,MALDI-TOF MS datas,calculation results of Fukui Function and atomic dipole moment corrected Hirshfeld population method confirmed the sensing mechanism of Probe 2 for biothiols and H2S.Finally,Probe 2 could be used to separately sense intracellular GSH,Cys and H2S.4.On the basis of the previous chapter,we changed the sensing group,and prepared a fluorescent Probe 3.which has a 1.2,4-triazolyl group.It could also separately detect the contents of Cys,GSH and H2S.Moreover,Probe 3 could display off-on fluorescence toward Hcy with the use of CTAB,and thus could determine the total contents of Hcy and GSH,Finally,this probe was successfully applied for the bioimaging of Cys,Hey(CTAB),GSH and H2S in HeLa cells.