| Hydrogen peroxide(H2O2)is an important reactive oxygen species and plays an important role in the physiological and pathological processes of the human body.In the process of cell growth,proliferation and differentiation,on the one hand,H2O2 participates in signal transmission through oxidative phosphatase and thioredoxin,on the other hand,excessive H2O2 can cause oxidative damage to cells,trigger apoptosis and necrosis,and lead to various diseases production,such as cardiovascular and cerebrovascular diseases,cancer,inflammation,etc.In addition,H2O2 also plays an important role in food safety and other fields.Adding H2O2 to food can effectively inhibit bacterial reproduction and prolong the shelf life of food.However,the illegal use of H2O2 in food also poses a great threat to human health,such as accelerating human aging and inducing various diseases.Therefore,the development of efficient detection methods to meet the detection of H2O2 in the actual system is of great significance for elucidating its biological role and ensuring food safety.In recent years,fluorescence analysis has been widely used in the detection of H2O2 in complex systems such as cells,subcellular organelles,and food due to its advantages of high sensitivity,good selectivity,and low detection cost.However,traditional H2O2 fluorescent probes mainly respond irreversibly,and it is difficult to detect the dynamic changes of H2O2,which poses certain challenges for exploring the complex biological effects of H2O2.Based on this,this thesis designed and synthesized two organelle-targeting reversible H2O2 fluorescent probes to realize the detection of intracellular H2O2 and GSH redox cycles,as well as the detection of H2O2 in food.The specific work is as follows:(1)Mitochondria are the energy factories of cells and the main place for the production of H2O2.The abnormal increase of ROS will lead to a series of physiological and pathological phenomena such as mitophagy.To further explore the effect of dynamically changing mitochondrial H2O2 on mitochondrial structure and function,we designed and synthesized a mitochondria-targeted reversible H2O2 fluorescent probe.The probe uses a naphthalimide fluorophore,benzisoselenazolone as a recognition group,and triphenylphosphine as a mitochondrial targeting group.Due to the photo-induced electron transfer(PET)effect,the probe’s self-fluorescence is very weak,and the probe’s fluorescence is significantly enhanced by the redox reaction with H2O2.The enhanced fluorescence can in turn be quenched in the presence of GSH,and the molecular structure returns to the probe.Therefore,this probe can realize the reversible detection of H2O2.The probe has high sensitivity for H2O2 detection with a detection limit as low as 3 nM.The probe successfully achieved real-time imaging of the dynamic changes of H2O2 in cells.In addition,the probe was successfully used for the detection of H2O2 in milk with satisfactory results.(2)Lysosomes play the role of recycling bins and intracellular metabolic signaling centers in organelles.To further realize real-time monitoring of H2O2 in lysosomes,we designed and synthesized a lysosome-targeting reversible H2O2 fluorescent probe.The probe uses morpholine group as lysosome targeting group,naphthalimide as fluorophore,and benzisoselenazolone as recognition group.Similar to the above-mentioned mitochondria-targeted H2O2 fluorescent probe,this probe can also realize the reversible detection of H2O2.The probe has high sensitivity for H2O2 detection with a detection limit as low as 7 nM.Imaging of cellular colocalization indicated that the probe was mainly located in lysosomes.The probe successfully realized the reversible detection of H2O2 in lysosomes,which provided an effective tool for further exploration of lysosomal oxidative stress. |
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