New Type Of Boron Containing Two Fluorine Structure Fluorescent Probe Design Synthesis And Its Application In Bioactive Substances Detection And Imaging

Various free radicals were produced in the metabolic processes of organisms, Theyplay a very important role in maintaining the body’s normal physiological functions.Under normal circumstances, the content of free radicals was in a balanced level.They are involved in cell signal transduction, in vivo synthesis and metabolism ofmaterial and energy, but the content of an imbalance will lead to the dysfunction ofthe body to induce various diseases. Singlet oxygen （1^O₂） is one of the active oxygenspecies （ROS）. In recent years, much studies have confirmed that1^O₂participates inthe immune system modulation, gene expression and cell growth regulationMeanwhile,1^O₂is widely used to kill cancer cells in the photodynamic therapy.However, if excessive1^O₂exists, they can cause disease, such as erythropoieticprotoporphyrin, and skin cancer, etc. Therefore, the establishment of an effectivemethod for the detection of1^O₂in biological systems has important biological andpathological significance.Fluorescence probe based detection is characteristic of simple and easy operation,high sensitivity, wide dynamic range and low cytotoxicity. When labeled an analyte,the changes of fluorescence intensity or excitation and emission wavelength of probegive information of the analyte concentration. When coupled with the laser confocalimaging technique, in situ and real time imaging of analyte was achieved with highsensitivity and selectivity. Therefore, the development of fluorescent probes for highlyactive, short-lived radicals in living cells shows great potential in the fields ofbiological and chemical research.Based on the highly sensitive and highly specific characteristics of the fluorescentprobes, and combined with it can be used for biological live cell confocalfluorescence imaging, this thesis carried out the following two aspects of the researchwork:First, the research progress of free radicals in the fields of physiology andpathologyl and their detection techniques are reviewed. Specific attention was givenon singlet oxygen and its detection techniques. After that, the progress on difluoroboron-based fluorescent probes and their application in biological analysis isalso reviewed.Second, the design and synthesis of a new fluorescent probe （DFBA） for thedetection of singlet oxygen is accomplished. The new fluorescent probe DFBA issynthesized through combining anthryl group and difluoroboron compounds. Theinitial fluorescence of DFBA is low because of the photoinduced electron transfer（PET）, but is significantly enhanced when anthracene is oxidized to the endoperoxideand PET is restrained in the presence of singlet oxygen, so as to achieve thequalitative and quantitative detection of1^O₂. The probe shows a high selectivity for1^O₂over other competitive free radicals、reducing substances （glutathione, L-ascorbicacid） and metal ions. The standard equation is F=47.26+7.16[1^O₂]（μM） （R=0.9990）with the linear range and detection limit of 6.0×10^-77.2×10^-6M and 75 nM,respectively. More important is to the probe can reaction with1^O₂instantaneously andrapidly, which can capture of the high activity and short-lived1^O₂, so it is conduciveto the in situ detection. MTT assay suggests DFBA is low toxicity. Using confocalfluorescence imaging, the singlet oxygen that produced in the PMA-stimulatedmurine macrophages （RAW 264.7） is analyzed successfully. Consequently, weprovide a suitable fluorescent probe which is usded to study the physiological andpathological functions of1^O₂.