The Synthesis And Characterization Of Fluorescent Sensors Based On Fluorescein And Application To Image In Living Cells

Fluorescent probe, also namely fluorescent sensor, is a new chemical detection method, which plays an important role in clinical biochemistry and environment science owing to the merit of high selectivity, high sensitivity, real-time response and convenient operation. Recently, it has become one of the hottest topics to design fluorescent sensor in chemistry and biology. Because of the excellent fluorescent properties, fluorescein derivatives have been widely utilized in many fields. At present, they are also paid more attention to fluorescent chemosensors’design. Fluorescein compounds are attractive candidates of fluorescent probes owing to their good photophysical properties with strong fluorescence, large molar extinction coefficient, excitation and emission in visual field, no toxic side effect. Based on that, in this thesis three fluorescein-based fluorescent sensors for ions or small molecular with high selectivity and sensitivity have been designed and synthesized.The thesis includes the following four parts:1. A briefly introduce of the basic concept, important properties and research fields of fluorescent sensors. The fluorescein derivatives and the application to image in living cells were reviewed.2. A new sulfide ion (S2-) fluorescent sensor L1Cu was designed and fully characterized. UV-vis and fluorescence spectroscopy displayed that the sensor can detect sulfide ion (S2-) with high selectivity and high sensitivity among all kinds of anions and different salt cantaining sulfide in PBS media. Job’s plot, ESI-mass and DFT calculation demonstrated the coordination mode and interaction mechanism. Cells imaging experiments indicated that probe L1Cu can identify sulfide ion (S2-) in cells, which revealed that this probe have a potential value of biological applications.3. Two new fluorescein derivatives L2and L3were developed. L2can indicate copper ions (Cu24) and hydrogen sulfide (H2S) in turn with a bidirectional "On-Off-On" fluorescent property. UV-vis and fluorescence spectroscopy showed that the sensor can detect copper ions (Cu2+) and hydrogen sulfide (H2S) with high selectivity and high sensitivity. Cells imaging experiments indicated that probe L2can pass through epicyte and identify copper ions (Cu2+) and hydrogen sulfide (H2S) in living cells.4. Anovel ClO-fluorescent probe L4was designed and synthesized. Fluorescence and UV-vis spectra showed that the probe can detect CIO-with high selectivity and high sensitivity in Na2B4Q7media utilizing deprotection mechanism. Furthermore, the fluorescent sensor is to the naked eye detection. This will be in the actual production and life which has a very wide range of applications.