Synthesis And Properties Of Fluorescence Probes For Detecting HClO/H₂S

Fluorescence probes has become an indispensable tool for studying the physiological and pathological processes of organisms.Hypochlorous acid(HClO)and hydrogen sulfide(H₂S),as important reactive oxygen species and reactive sulfur species in organisms respectively,play an important role in maintaining the normal operation of the organism's life system.HClO mainly acts on the body's immune system.Abnormal concentration of HClO in the body can cause lung damage,cardiovascular disease,cancer and so on.H₂S is mainly used as an important gas transmitter in organisms,and plays an important role in vasodilation regulation,inflammatory stress response,and neuromodulation.Abnormal concentration of H₂S can cause Alzheimer's disease,diabetes,Down syndrome and so on.In addition to their respective important roles in organisms,HClO and H₂S are also closely related to each other.The oxidative and reductive properties of HClO and H₂S make them easy to participate in redox reactions in vivo,so HClO and H₂S play an important role in maintaining redox homeostasis of cells.Intracellular redox homeostasis controls many important biological processes and plays an important role in diseases such as inflammatory diseases,cancer and neurodegenerative diseases.Therefore,developing the fluorescence probes that can simultaneously detect HClO and H₂S has important practical significance for cell physiology research.In this paper,three kinds of fluorescence probes for identifying HClO and H₂S based on different sensing mechanisms were synthesized,and their spectral properties and sensing mechanism were studied.In Chapter 2,a ratiometric fluorescent probe 1A for HClO was synthesized based on the FRET mechanism through connecting the naphthalimide and rhodamine fluorophores.After the probe reacted with HClO,the fluorescence of the probe changes from blue to red,indicating that the probe has a large pseudo-stokes shifts,which can effectively resist the interference of external factors and improve the accuracy of probe recognition.At the same time,the probe shows excellent selectivity and sensitivity to HClO,and the detection limit is as low as 4.5 n M.In Chapter 3,a fluorescent probe 1B that can recognize HClO and H₂S with different fluorescent signals was synthesized through connecting coumarin and rhodamine fluorophores.The probe recognizes H₂S and emits blue fluorescence under excitation at 380 nm;recognizes HClO and emits red fluorescence under excitation at530 nm.At the same time,the probe can respond to HClO and H₂S quickly,and the fluorescence reaches a steady state within 2 minutes.Cell imaging experiments and test paper tests also confirmed the potential of the probe.In Chapter 4,a fluorescent probe 1C that can continuously recognize HClO and H₂S was synthesized through connecting the naphthalimide and cyanine fluorophores.Based on the FRET and ICT mechanism,the probe responds to HClO and H₂S quickly in two emission bands and can continuously identify HClO and H₂S with multiple fluorescent signals.Cell imaging experiments show that the probe can detect HClO and H₂S in living cells.