【作者】 刘田宇；

【导师】 崔京南；

【作者基本信息】 大连理工大学 ， 精细化工， 2013， 博士

【摘要】 近些年,荧光探针领域因在化学传感、光学材料以及生物学领域具有广泛的应用而发展迅速。然而,大多数探针缺乏特异的靶向性,且不能提供客体分布的定量信息。迫切需要开发出具有细胞器定位功能以及能够定量反映客体分布的荧光探针。粘度在生理过程起着至关重要的作用。因此,开发出具有定量检测生物体内粘度分布情况,以及实时监控生物体内粘度变化探针已经成为趋势。大多数的粘度探针设计是基于扭曲分子内电荷转移机理(TICT),存在检测信号不灵敏、易受染料浓度干扰和细胞渗透性差等缺点。光致电子转移(PET)是典型的被用来设计荧光传感器的方法之一,具有灵敏度高和响应时间快等优点。所以,本文设计合成了两类可用于生物体内具有特定功能的荧光探针,一类是基于PET和FRET机理设计的比率型探针,可以定量反映细胞内粘度的分布；另一类是能够定位于溶酶体内检测硫化氢的荧光分子探针。1、基于PET机理和FRET机理,设计合成了比率型粘度探针VN-1。将苯胺作为PET电子供体,葸和1,8-萘酰亚胺分别作为PET电子受体和FRET的供-受体对。随着溶剂粘度的增加以及温度的降低,探针VN-1中1,8-萘酰亚胺和葸的荧光信号呈现比率的变化。与参比化合物VN-2和VN-3比较得知,探针VN-1中TICT的抑制促进了荧光增强。通过不同激发波长实验以及单晶研究,确认FRET在探针VN-1中高效发生。探针VN-1对pH、金属离子和生物大分子均不敏感。通过荧光寿命的研究以及理论计算可以从另一个角度解释探针VN-1中PET的作用机理。2、相比于另外几个探针,VN-1能够更好地反映细胞内粘度分布。在不同种类的细胞中,探针VN-1与商品化染料的共定位实验表明,溶酶体粘度最大,其次是线粒体。利用双光子比率成像和荧光寿命成像,探针VN-1可以反映细胞内粘度的分布情况,验证了溶酶体粘度最大的结论。在细胞凋亡实验中,利用双光子比率成像和荧光寿命成像观察到细胞内整体荧光强度且荧光寿命增加,这表明细胞内粘度增加。而溶酶体观察到的现象与上述相反,表明其粘度减小。3、以1,8-萘酰亚胺为母体设计合成了识别硫化氢的反应型探针NI-NSH和lyso-NSH。将具有溶酶体导向性的吗啉环引入探针lyso-NSH中,与参照化合物NI-NSH相比,其在溶酶体pH范围内荧光信号稳定。探针lyso-NSH和NI-NSH在牛血清中对硫化氢表现出良好的识别性质。与硫化氢结合后,探针lyso-NSH和NI-NSH双光子吸收截而积分别增加至175GM和186GM。与商品化染料的共定位实验表明,探针lyso-NSH可以在溶酶体中识别外加的硫化氢。更多还原

【Abstract】 In recent years, the field of fluorescent probe is developing very fast. It was widely applied in chemical sensing, optical materials and biology. However, there are no targeting and quantitative information of the distribution of object can be recieved from most probes. So there is an urgent demand of the fluorescent probes which have the cell organelle positioning function and provided the quantitative information of the object distribution. It plays a vital role for viscosity in physiological processes, so it is important for people to develop the probes which can detect the distribution of intracellular viscosity and real-time monitor the viscosity changes in vivo. The mechanism of the most viscosity probes is based on the twisted intramolecular charge transfer mechanism (TICT). But there are some disadvantages. For example, signal insensitivity, susceptible interference by dye concentration, poor cell permeability and so on. Photoinduced electron transfer (PET) is one of the typical methods which are used to design fluorescent probe. PET usually has the advantages of high sensitivity and fast response time. So we developed two types of fluorescence probes with specific function in cells. One probe, based-on PET mechanism and FRET mechanism, can quantitatively be detected the viscosity distribution of total cells, the other can be located in lysosome to detect H2S.1. We designed and synthesized a ratiometric viscosity probe VN-1based on PET and FRET mechanism. Aniline was used as an electron donor,1,8-naphthalimide fluorophore and anthracene fluorophores were used as electron acceptor and as acceptor and donor for FRET. Probe VN-1performed strong fluorescence enhancement as the increasing of solvent viscosity and decreasing of temperature. The probe showed the ratiometric changes. Compared with compounds VN-2and VN-3, fluorescence enhancement of VN-1probe is mainly owed to PET and TICT inhibition. Through the analysis of the probe crystal and measurements at different excitation wavelength, we deduce that efficient FRET happened. Probe VN-1was insensitive with pH, metal ions and biomolecules which can provide its application in cells. Fluorescence lifetime studies and theoretical calculations about VN-1can be explained the PET mechanism in the viscosity of the environment from another point of view. 2. The probe VN-1was well used in cells to reflect the intracellular viscosity distribution. Probe VN-1can reflect the different viscosity distribution by a fluorescent signal in different types of cells. The colocalization experiments showed that brightest region is lysosomes, followed by the mitochondria. The probe VN-1can be used with two-photon ratio image to detect the viscosity distribution. It also showed the highest viscosity of lysosomes. We applied VN-1in MCF-7cells to focus on viscosity changes during the process of apoptosis. The fluorescence intensity and lifetime increased of the total cells in the process of cell apoptosis observed by two-photon ratio imaging and fluorescence lifetime imaging, which means the viscosity within cells increased. But the phenomenon in lysosome was opposite from the above which means its viscosity decreased.3. We designed and synthesized two hydrogen sulfide-detecting reaction-based probes (NI-NHS and lyso-NHS). Probe lyso-NHS is composed of morpholine ring which used as lysosomal orientation. Comparing with NI-NHS, Lyso-NHS showed stable fluorescence signal at lysosome pH range. They performed good hydrogen sulfide detecting in the bovine serum. Two-photon absorption cross-section of both NI-NSH and lyso-NSH increased to175GM and186GM respectively after detecting hydrogen sulfide. In colocalization experiments compared with commercial dyes, it showed that lyso-NHS detected hydrogen sulfide located in lysosomes.更多还原