Novel Fluorescent Probe For Sulful Dioxide And Its Application In Biological Imaging

In recent years,more and more epidemiological evidences show that Sulfur dioxide(SO₂)as an active signaling molecule,participates in many important physiological and pathological processes in the human body,and plays an extremely essential role in them.In addition,SO₂is also closely associated with a variety of diseases and symptoms,such as cardiovascular diseases,neurological diseases,metabolic abnormalities and cancer so on.In order to study the unique function of active SO₂in biological environment and the relationship between it and biomolecules,it is necessary to develop molecule tools that can rapidly detect SO₂in living cells.Therefore,the detection of SO₂in living cells is taken as the research purpose,and fluorescence probe analysis is taken as the methods,and three fluorescent probes were designed and synthesized by comprehensive use of molecular recognition and molecular fluorescence response mechanism,The specific research contents are as follows:1.A fluorescent probe Mito-AS-SO₂of mitochondria targeting was designed and constructed,which was easily by one-step reaction.The probe used carbon-carbon double bond as the reactive site of SO₂and Michael addition reaction as the response mechanismt,so as to achieve the purpose of targeted detection of SO₂in living cells.In other words,when treated with Na HSO₃,its carbon-carbon bond will be attacked by the nucleophilic ions(HSO₃^-),resulting in a dramatic fluorescence decrease of the probe Mito-AS-SO₂.In addition,The probe Mito-AS-SO₂not only has the advantages of fast response,low cytotoxicity,high selectivity and low detection limit(3.37×10^-6M),but also has the ability to target mitochondria in living cells.The biological imaging results show that the probe has a high accuracy of targeting(the Pearson Correlation Coefficient is 0.90).These characteristics enable the probe to be successfully used to track SO₂in mitochondria of living cells.Thus,this probe provides a method for the targeted detection of SO₂in mitochondria of living cells,it is expected to become a powerful molecule tool for explore the relationship between SO₂and the function of organelle in living cells.2.Previous research demonstrated that fluorescence properties of the probe could be improved by changing functional groups.Accordingly,based on the design of probe Mito-AS-SO₂and changed the functional group reacted with4-(Diethylamino)salicylaldehyde,and constructed a mitochondria-targeted fluorescent probe Mito-AX-SO₂,which can quickly detect SO₂in mitochondria of living cells.This probe also used carbon-carbon double bond as the recognition site and Michael addition reaction as a response mechanism to effectively identify SO_2.The experimental results indicated that the probe Mito-AX-SO₂has good photostability,high selectivity,high sensitivity for the detection of SO₂,and its minimum detection limit go down to 6.15×10^-6M.Besides,the biological imaging experiment show that the probe can achieve rapid targeting detection of SO₂,and the targeting location is accurate(Pearson's coefficient is 0.81).Therefore,this research provides some basic methods for the study of physiology and pathology of SO₂at the subcellular level.3.A novel fluorescent probe HQ-SO₂was developed by connecting a benzene ring and a benzopyran salt bridge,which using the mechanism of Michael addition reaction and utilizing benzopyran as the reactive site for its electrophilic property.In the presence of Na HSO₃,the carbon-carbon double bond of the probe will be attacked by the nucleophile ions(HSO₃^-),which broke the conjugation system,and finally leaded to the fluorescent intensity of the probe HQ-SO₂sharply decrease.Moreover,the probe HQ-SO₂also has excellent advantages,such as fast response,high sensitivity,low detection limit(6.29×10^-6M)and low cytotoxicity.Thus,this research provided a method and basis for the development of SO₂fluorescent probe,or will provide an underlying application in future pathological research and biomedical diagnosis.