The Design,Synthesis And Application Of Fluorescence Probes For Reactive Sulfur Species

H₂S?Hydrogen Sulfide?and SO₂?Sulfur dioxide?,as the important reactive sulfur species in the body,has been proven to be involved in many physiological activities.As gas signal molecules in the body,the right amount of H₂S and SO₂ could adjust vasodilatation and blood pressure,resistance play anti-inflammatory effect,reduce ischemic reperfusion injury and resist oxidative stress.However,the high concentration of H₂S and SO₂ could cause poisoning in the respiratory,cardiovascular and nervous systems,which could make a variety of diseases.Therefore,it would be of great significance in clinical medical research for in-situ imaging of H₂S and SO₂ by fluorescent probes.For this reason,we designed and synthesized a series of different H₂S and SO₂ fluorescent probes based on the unique chemical properties of H₂S and SO₂,and further applied these probes on the detection and imaging of cells and in vivo.The specific research works are as follows:1.Owning good optical properties,good solubility and low cytotoxicity,the quinoline ring was designed to be the parent of the "turn on" fluorescent probe QN-1 with good water solubility.The probe QN-1 has faster reaction time?3.4 min?,lower detection limit?0.08 nm?and higher selectivity for H₂S in aqueous phase,indicating probe QN-1 had good water solubility and specificity for H₂S.It is worth mentioning that the probe QN-1 could be used for monitoring exogenous and endogenous H₂S in Hep G-2 cells.2.Based on the above work,we further optimized structure of probe and designed and synthesized a near-infrared and ratiometric fluorescent probe YC-1.After a series of optical tests,probe YC-1 showed faster reaction time?0.73 min?,lower detection limit?0.17 ?M?and higher selectivity for H₂S.In addition,it would show obvious color change and fluorescence change after the probe YC-1 responding to H₂S,which indicated the probe YC-1 could monitored the changes of the amount of H₂S by naked-eye.3.Considering the above,we designed a fluorescent probe PS-1 by combining quinoline and coumarin for the detection of the changes of SO₂ as the viscosity changes in living cells.After a series of optical tests,PS-1showed an obvious enhancement from 1.68 to 168.3 of fluorescence emission ratios at 475 and 643 nm(I₄₇₅/I₆₄₃).Besides,we found PS-1 exhibited fast response?less 15s?and low detection limit?17.7 n M?and higher selectivity for SO₂.After imaging in living cells,we found that the ratiometric fluorescence changes of PS-1 in the cells pre-incubated with nystatin were more obvious than that of no treated cells,indicating that internal increasing viscosity can induce increase the concentration of SO₂.