Construction And Application Of Bioactive Molecular Fluorescent Probes

Due to the adjustable structures,sensitive response,high selectivity,and excellent optical properties,small-molecule organic fluorescent probes have been widely applied in chemistry,life sciences and others fields.Meanwhile,the development of functional probes with practical value has become an important research subject.Reactive oxygen species(ROS)and reactive nitrogen species(RNS)are closely related to pathological processes such as Alzheimer’s disease,cancer,diabetes,cardiovascular disease and aging.Additionally,as an antioxidant and free radical scavenger,reactive sulfur species(RSS)plays a significant role in maintaining the redox homeostasis of living organisms.In order to explore the possible interaction between bioactive molecules and their pathological processes,two single functional probes and three multi-functional probes were designed and synthesized to detect the physiologically active substances in pathological processes.Furthermore,a "double check" fluorescent probe was developed to response human serum albumin(HSA),an early marker of diabetes,kidney disease,etc.The main research contents of this thesis paper are as described as follows:(1)The first dual-functional fluorescent probe(SZ)for detecting hydrogen sulfide(H2S)and peroxynitrite(ONOO-)was designed and synthesized.The probe SZ showed satisfactory selectivity and lower detection limit for ONOO-and H2S,respectively.In addition,SZ displayed low cytotoxicity and was successfully applied for endogenous and exogenous H2S and ONOO-imaging.Additionally,the application of this probe can monitor the fluctuation of ONOO’ and the protective effects of endogenous H2S in the carbonyl stress model that was induced by methylglyoxal(MGO).The advancement of this probe provided an effective tool for investigating the relationship between ONOO-/H2S and carbonyl stress.(2)A long-wavelength mitochondrial-targeted fluorescent probe TL for the detection of ONOO-was designed and synthesized.In the presence of ONOO-,the masking group phenylboronic acid pinacol ester of TL was removed and the fluorophore was released.With high selectivity,good sensitivity and fast response(about 50 seconds)for ONOO-,TL can achieve imaging exogenous and endogenous ONOO’ in living cells.What’s more,TL has been successfully applied to detect changes in the concentration of ONOO-in cells stimulated by dexamethasone.(3)The probe LR was designed and synthesized,and LR NPs were prepared by mixing with the F127 to detect hypochlorous acid(HClO).The particle size and morphology of nanoprobe LR NPs were determined by dynamic light scattering(DLS)and high-resolution transmission electron microscopy(HR-TEM).LR NPs displayed the advantages of high sensitivity,good selectivity and low detection limit,and have been successfully applied to detect endogenous and exogenous HClO in living cells.In addition,HClO concentration in HUVECs induced by Hcy was successfully detected by the nanoprobe.(4)Based on coumarin and rhodamine as fluorophores,two cases of dual-function fluorescent probes(DURB and DURC)were designed and synthesized to identify HClO and ONOO-.Probe DURB used thiolactone and diphenylphosphinyl as recognition sites for HClO and ONOO-,respectively.On the other hand,probe DURC used dimethylaminothioformyl and hydrazide as recognition sites for HCIO and ONOO-.Probe DURC can detect HCIO and ONOO-separately or simultaneously,and the detection limits of HClO and ONOO-were 58.6 nM and 89.3 nM,respectively.Probe DURC was also successfully used for the detection of intracellular HClO and ONOO-in living cells.(5)Based on naphthimide and spiropyran,two new light-controlled fluorescent probes,namely HSP and MSP were designed and synthesized.The probe HSP displayed a unique "double check" mechanism for the detection of Human Serum Albumin(HSA),which can avoid false positive signal interference.In the presence of HS A,the probe HSP displayed a significant green fluorescence emission enhancement at 540 nm.After with UV irradiation,which displayed a strong red fluorescence emission enhancement at 610 nm.The binding sites of probes HSP and HSA were determined by molecular docking and theoretical calculations.The practical applications show that probe HSP can sensitively detect HSA in urine and human serum sample.Most importantly,the HSP/HSA complex displayed good lightcontrolled reversibility and can be applied to monitor the level of SO2 in living cells.