Active Oxygen Free Radicals In Cells Detection Design Synthesis And Applications Of Fluorescent Probe

Redox metabolic processes of living organisms produce a variety of free radicals,including superoxide anion (O2-·), hydrogen peroxide (H2O2), hydroxyl radical (·OH),singlet oxygen (1O2), lipid peroxide radicals (ROO·), and nitric oxide (NO·), etc. Theseradicals are usually active and can react with a variety of biological molecules therebychange the physical and chemical properties of these macromolecules. The radicalsproduced through non-enzymatic reactions and enzymatic oxidation-reduction reactionsdramatically influence the physiological and pathological processes of living cells.Meanwhile, the cells also rely on some of the reducing substances (such as GSH, NADPH,etc) to maintain a strong antagonistic oxidation, self-repair and the redox balance.However, when the reducing substances express at excessive levels, cells will suffer fromreduction stress, which breaks the cell’s redox balance, causing lesions to cells. Therefore,analytical tools or methods that can detect redox changes of living cells reversibly anddynamicly show high physiological and pathological significance. Because of the specialphotophysical and photochemical properties, small molecule fluorescent probes exhibitseveral advantages, such as easy synthesis, small steric hindrance, low cytotoxicity, andmultiple recognition sites, etc. Combined with the laser confocal imaging technique, freeradicals in the intracellular compartments can be analyzed in situ with high sensitivity.Therefore, this thesis carried out the following the aspect of the research work:The design and synthesis of a near-infrared fluorescent probe (An-Cy) for the detectionand imaging of singlet oxygen in living cells is accomplished. A near-infrared fluorescentprobe An-Cy that synthesized through combining anthryl group and cyanine is proved tobe a turn-on type probe for singlet oxygen. The initial fluorescence of An-Cy is low, butis significantly enhanced in the presence of singlet oxygen (λex/λem=740/805 nm). Thestandard equation isΔF= 877.7+ 443.0[1O2](μM) with the linear range and detectionlimit of 1.0×10-7~ 3.0×10-6M and 51 nM, respectively. Using confocal fluorescenceimaging, the singlet oxygen that produced in the PMA-stimulated murine macrophages (RAW 264.7) is analyzed successfully. The results provide an ideal fluorescent probe andcorresponding analytical method for the analysis of singlet oxygen in living cells andorganisms, and exhibits important practical significance.