Design,Synthesis And Bioimaging Of Fluorescent Probes For Reactive Oxygen Species

Reactive oxygen species play an important role in living organisms and act some significant parts in cell growth,proliferation,host defense,and signaling pathways under physiological conditions.Hydrogen peroxide?H₂O₂?and hypochlorous acid?HOCl?are important low molecular reactive oxygen species in the biological body,which have crucial physiological functions and participate in many physiological processes.Once,the concentration of hydrogen peroxide or hypochloric acid in the cell is abnormal,it will cause various tissue damage and cause various diseases.It is very important to monitor H₂O₂ and HOCl in living organisms.Sulfur dioxide?SO₂?,as a new recognized gas signal molecule,plays an important role in regulating cardiovascular function.Therefore,it is also significative and value to use effective molecular tools to elucidate the production and physiological functions of sulfur dioxide and its derivatives.In this thesis,fluorescent probes based on molecular recognition and molecular fluoresence sensing principle for H₂O₂,HOCl and SO₂ detection in cells and organisms are developed.The research contents are as follows:We reviewed for the recognition mechanisms of fluorescent probes and the research progress on the application of the H₂O₂ and HOCl flurorescent probes.Based on the AIE properties of tetraphenylethene derivatives and ESIPT mechanism,three flurorescent probes TPE-H2O2-N,TPE-H2O2-O and TPE-H2O2-S are designed and synthesizedfor H₂O₂ detection.The focus research is about the optical properties of probe TPE-H2O2-S for H₂O₂ detection.Besides,probe TPE-H2O2-S issuccessful to use into the ratiometric imaging of H₂O₂ in RAW264.7and HepG2 cells.Based on the monomer/excimer properties of pyrene derivatives,probe Py-Boe with large Stokes shift is designed and synthesizedfor H₂O₂ detection.Probe Py-Boe exhibits excellent photostability,high sensitive and selectivity in pure water.The detection limit for Py-Boe is calculated to be 6.7?M.Besides,the probe Py-Boe achieves successfully imaging of H₂O₂ in living RAW 264.7 cells.Based on FRET mechanism and rhodamine ring opening processes,a new ratiometric lysosomal-targeted fluorescent HOCl probe?Lyso-HOCl?is designed and synthesized Naphthalene derivative served as the energy donor and a rhodamine fluorophore was chosen as the energy acceptor.Morpholine as targeting group that can increase the probe distribution in lysosome.In the presence of HOCl.ProbeLyso-HOCl exhibits a ratiometric fluorescence response with excellent selectivity.In visible light,probe Lyso-HOCl can be observed that solution color changes from colorless to red.With the naked eye.Besides,the probe can be used for ratiometric fluorescence imaging endogenous HOCl with high colocalization coefficient compared with lysosomal localization dye.Based on the AIE properties of tetraphenylethene derivatives and ESIPT mechanism,a ratiometric flurorescent probe TPE-SO2is designed and synthesizedfor SO₂detection.ProbeTPE-SO2 exhibits a ratiometric fluorescence response with excellent selectivity.The detection limit for TPE-SO₂ is calculated to be 0.9?M.Besides,probe TPE-SO2issuccessful to use into the ratiometric imaging of SO₂ in living cells?RAW264.7,HepG2 and HeLa?and live zebrafish.