Construction Of Novel Reactive Sulfide Species(RSS) Fluorescent Probes And Study Of Their Bioimaging Applications

Reactive sulfide species（RSS）play an important role in the physiological metabolism of life,and the detection of these small molecules by fluorescence probes has great advantages such as high sensitivity,simple operation,easy synthesis,high selectivity,good tissue penetration and low biotoxicity,etc.The detection of RSS in the physiological environment by using organic small molecule fluorescent probes therefore is a significant tool for scientists to understand and study the relevant life activities.In this work,three organic small-molecule fluorescent probes with excellent performances have been rationally constructed and studied for their optical properties and applications in bioimaging.（1）A NIR ratio-metric sulfur dioxide fluorescent probe HSU-3 with endoplasmic reticulum targeted was rationally constructed based on FRET fluorescence delivery mechanism.Spectroscopic test results showed that the probe HSU-3 has the advantages of a low detection limit,excellent selection specificity and good resistance for acid and base.In addition,the probe HSU-3 has low cytotoxicity and can therefore be used for cells and in vivo imaging,as well as tracing of SO₂ on the endoplasmic reticulum.（2）A multi-detection fluorescent probe HSU-QD was constructed using coumarin moiety as the fluorescence platform to differentiate Cys/GSH/HSO₃^-.The results of fluorescence spectroscopy and UV-absorption tests showed that the probe was capable to simultaneously detect the three compounds by different changes in fluorescence signals after interacting with each of them.The same results can be obtained in confocal fluorescence imaging experiments of Hela cells.（3）Based on the ICT fluorescence mechanism,a novel mitochondrial-targeted NIR hydrogen sulfide fluorescence probe HSU-NIR-Cys was constructed,and the optical performance test results showed that the fluorescence intensity of the probe increased significantly with the increase of HS^-（Na HS as releasing agent）concentration and red-shifted phenomenon.The probe was also able to detect endogenous and exogenous H₂S in living cells and in vivo.In addition,the probe had excellent photoacoustic properties and was capable to monitor the level of H₂S in diseased tissues and tumors by photoacoustic imaging.