【作者】 李季；

【导师】 曾宪顺；

【作者基本信息】 天津理工大学 ， 凝聚态物理， 2021， 硕士

【摘要】 近年来,荧光探针具有高灵敏度、可设计性、无创检测等优点,因此在分析和生物化学中得到了广泛的应用。作为传统花菁染料的重要一员,半花菁染料具有大的斯托克斯位移、大的摩尔消光系数和结构可调等优点,从而被广泛开发为荧光探针。但基于半花菁染料构建的荧光探针中,仍存在水溶性不好、光稳定性差、发射波长较短、具有较强溶剂效应等问题,在实现生物分子和细胞微环境检测以及亚细胞水平细胞器靶向应用方面受到了局限。基于此,本论文设计合成了可降低溶剂化效应的四个新型半花菁荧光染料,为目前半花菁染料在构建荧光探针中出现的不足提出新的解决思路,本论文主要开展了以下工作:(1)通过将含有刚性大π共轭分子骨架的3-苝甲醛与N-甲基苯并噻唑和N-甲基苯并吲哚反应,合成了具有典型D-π-A构型的探针PeBt和PeBi,并系统研究其光物理性能及成像性能。探针PeBt和PeBi在水溶液中最大发射波长分别位于723 nm和606 nm。且探针PeBt的Stokes位移达到196 nm,这有助于提高生物成像的信噪比。另外,由于分子内含有大π共轭体系的原因,两种半花菁染料均具有较弱的溶剂化效应。在细胞成像实验中,探针PeBt和PeBi表现出低细胞毒性、良好的膜透性。并且与商用定位剂相比,探针PeBt和PeBi具有良好的光稳定性。此外,探针PeBt和PeBi实现了靶向定位于溶酶体和线粒体。且探针PeBt成功应用于细胞凋亡过程中溶酶体动态变化的监测。因此为构建功能性溶酶体和线粒体靶向荧光探针提供了重要平台。(2)设计并合成了可靶向标记线粒体的粘度敏感型荧光探针PyQz和PeI。基于TICT机制,探针PyQz和PeI在水溶液(1.00 cP)中显示出较低的荧光强度。而在95%丙三醇溶液(523.00 cP)中,两种探针分别在600 nm和737 nm处表现出明显的荧光增强。同时,探针PyQz和PeI具有优异的光物理性能,包括较弱的溶剂化效应、不受生理pH的影响、大的Stokes位移、良好的特异性和抗干扰能力。此外,探针PyQz和PeI实现了活细胞内粘度的荧光成像检测,并且成功地被用于检测莫能菌素引起的线粒体粘度异常变化。更多还原

【Abstract】 Fluorescent probes,which featured with the inherent superiorties including high sensitivity,designable and noninvasiveness,had recently wide application in analytical and biological chemistry.As an important part of traditional cyanine dyes,hemicyanine fluorescent dyes have been widely developed as fluorescent probes for the large Stokes shift,large molar extinction coefficient and adjustable structure.However,fluorescent probes based on hemicyanine dyes sometimes showed poor water solubility,low photostability,short emission wavelength and strong solvent effect,and could not be applied to the detection of biomolecular and cellular microenvironment and the targeting of subcellular level organelles.Based on this,four novel hemicyanine fluorescent dyes which could reduce the solvation effect have been designed and synthesized in this paper,and a new solution was proposed for the deficiency of hemicyanine dyes in the construction of fluorescent probes.The paper mainly carried out the following work:(1)The probes Pe Bt and PeBi with typical D-π-A system were synthesized by the reaction of 3-Perylenecarboxaldehyde containing a rigid large π-conjugated molecular skeleton with N-methylbenzothiazole and N-methylbenzoindole,and were systematically studied its photophysical performance and imaging performance.The maximum emission wavelengths of probes PeBt and PeBi in aqueous solution were723 nm and 606 nm,respectively.The Stokes shift of probe Pe Bt reached 196 nm,which would help increase the SNR of biological imaging.In addition,due to the large π-conjugated system,the two fluorescent probes had weak solvent effect.In living cell imaging experiments,the probes PeBt and PeBi showed low cytotoxicity and good cell permeability.Compared with commercial localizers,the probes PeBt and PeBi had excellent photostability.In addition,the probes PeBt and PeBi were targeted to lysosomes and mitochondria,respectively.The probe PeBt was successfully used to monitor the dynamic changes of lysosomes in the process of apoptosis.These results provide a significant platform for the construction of functionally mitochondria and lysosome-targetable fluorescent probes.(2)We designed and synthesized the mitochondria-targetable and viscosity-sensitive fluorescent probes PyQz and PeI.Based on TICT mechanism,the probes PyQz and PeI showed a weak fluorescence at a viscosity value of 1.00 cP,and the fluorescence intensity increased significantly at 600 nm and 737 nm in 95%glycerol solution,respectively.At the same time,the probes PyQz and PeI had excellent photophysical properties,including weak solvent effect,not being affected by physiological pH,large Stokes shift,excellent selectivity and anti-interference ability.Additionally,the probes PyQz and PeI have been successfully used to monitor the viscosity changes of mitochondria caused by the addition of ionophores(monensin).更多还原