Construction Of Ratiometric Fluorescent Probes For Hydrogen Polysulfides

Hydrogen sulfide?H₂S?,as an important endogenous gasotransmitter in human body,plays important roles in physiological and pathological process.H₂S is easily oxidized by reactive oxygen species?ROS?into Hydrogen polysulfides?H₂S_n,n>1?under physiological conditions.Therefore,the detection of H₂S dynamic balance in vivo is mainly to detect the presence of H₂S and H₂S_n.Fluorescence method has received considerable attention due to its advantages including excellent sensitivity,high selectivity,wide linear range and convenient operation,especially its real-time monitoring.To give accurate information of H₂S_n via fluorescence method,in this thesis,we report the design and synthesis of ratiometric fluorescent H₂S_n probes1.A new ratiometric fluorescent polysulfides probe,RP-A was designed and synthesized.RP-A showed rapid and specific ratiometric response towards polysulfides over other biologically related species such as RNS,ROS,RSS and other ions.The observed pseudofirst-order rate constant for the reaction of RP-A with polysulfides was calculated to be 0.071 min^-1,and the detection limit of RP-A was determined to be 57 nM.Moreover,the intracellular polysulfides imaging ability of RP-A was demonstrated in HeLa cells via confocal fluorescence microscopy imaging.2.An isophorone-based far-red emitting fluorescent probe?RP-B?was designed and synthesized for selective ratiometric sensing and imaging of H₂S_n.RP-B shows rapid and specific ratiometric response towards H₂S_n,over other biological related species such as RNS,ROS,RSS and ions.The observed pseudo-first-order rate constant for the reaction of RP-B with H₂S_n was calculated to be 0.096 min^-1,and the detection limit of RP-B was determined to be 43 nM.Moreover,the intracellular H₂S_n imaging ability of RP-B has been demonstrated in HeLa cells via confocal fluorescence microscopy imaging.