【作者】 王慧；

【导师】 田文晶；

【作者基本信息】 吉林大学 ， 高分子化学与物理， 2017， 硕士

【摘要】 荧光生物探针作为荧光生物传感和光学成像技术中的重要信号媒介,不仅能对生物样品在分子水平上进行可视化分析,而且能对复杂的生物结构/过程进行深入研究。生物传感和成像的选择性主要通过探针和待分析物的相互作用实现,而灵敏度则通过探针与待分析物结合前后的荧光对比度来实现。大部分传统荧光探针和待测生物样品结合时发生聚集,导致荧光淬灭,这种低灵敏的―Turn-Off‖荧光变化模式严重缩小了探针的实际应用范围。聚集诱导发光(Aggregation-Induced Emission,AIE)为聚集态荧光淬灭这一难题提供了直接有效的解决途径。在荧光生物分析中,AIE现象的发现为发展新型生物荧光探针,允许高浓度探针用于生物传感和光学成像做出巨大贡献。简洁的传感策略设计和―Turn-On‖的荧光变化模式大大提高了探针在生物学应用研究中的灵敏度。本论文以9,10-二苯乙烯基蒽作为基本骨架,引入不同的官能团或分子(季铵盐,吲哚美辛),得到具有AIE性质的新型荧光材料,并研究了这些材料在生物传感和光学成像中的应用。具体研究内容如下:1.对9,10-二苯乙烯基蒽进行季铵盐官能团修饰,合成了3种外围含有不同长度烷基链的季铵盐衍生物(DSAC2N,DSAC4N和DSAC6N),将其作为生物荧光探针;另外,制备了3种不同氧化程度的氧化石墨烯作为荧光淬灭剂和DNA链段识别因子。利用荧光生物探针,氧化石墨烯和DNA,构建新型非标记、点亮型DNA传感平台;通过调控DNA、荧光探针及氧化石墨烯三者间的超分子作用,研究超分子相互作用对核酸传感性能的影响,并最终实现高选择性、超灵敏检测目标DNA的目标,目标DNA的检测限低至0.19×10–9 M。2.以环氧化酶-2作为生物识别因子和成像靶点,设计合成了以吲哚美辛为环氧化酶-2的识别基团,9,10-二苯乙烯基蒽为发光基团的荧光生物探针NDSA。通过对环氧化酶-2的体外荧光响应实验,探究探针NDSA对环氧化酶-2的选择性荧光响应;通过探针NDSA的细胞生物学成像和毒性实验,发掘探针对癌细胞的亚细胞结构高尔基体的特异性标记能力和良好生物相容能力。更多还原

【Abstract】 Fluorescent bio-probes are important tools for bio-sensing and optical imaging,which allow direct visualization of bio-analytes at the molecular level and also offer insights into complex biological structures/processes.The sensing and imaging selectivity of the bio-probe is mainly determined by interactions between bio-probe and analytes,and the sensitivity is mainly determined by its fluorescence contrast before and after biomolecule binding.Emission from traditional fluorogen is quenched in its aggregate state,which compels many fluorogens to operate in a fluorescence ―turn-off‖ mode with a narrow scope of practical applications.Aggregation-induced emission(AIE)effect provides a straightforward solution to the aggregation-caused quenching phenomenon,also it makes great contribution to the development of new fluorescent bio-probes and allows the use of highly concentrated fluorogens for bio-sensing and imaging.The simple design of sensing strategy and fluorescence ―turn-on‖ property of AIE-active fluorogens largely improve the sensing sensitivity and easy-operation in biological applications.Herein,the fluorogens in my thesis are based on the 9,10-distyrylanthrance(DSA)molecule,which is an AIE-active material.By introducing various groups and small molecules(quaternary ammonium salt,indometacin)towards DSA unit,we obtain new fluorogens and also study their properties in bio-sensing and bio-imaging applications.Main Contents:1.Quaternized DSA derivatives(DSAC2N,DSAC4 N,and DSAC6N)with various lengths of alkyl chains substitute are served as fluorescent probes.Three graphene oxide(GO)samples with different oxidation degrees are used as DNA structure discrimination and fluorescence quenchers.We utilize ss DNA aptamer as the recognition element together with DSA derivatives and GO to construct the label-free and ―turn-on‖ DNA sensor for the detection of the target DNA sequence.We investigate the supramolecular interactions of DNA with AIE probe and GO to understand the sensing mechanism and optimize the sensing performance.By tuning these supramolecular interactions,we effectively improve the sensing sensitivity for target DNA sequence with the detection limitation as low as 0.17 × 10–9 M.2.By chosen cyclooxygenase-2(COX-2)as the biological recognition unite and imaging target,we obtain a novel AIE-active and COX-2-specific bio-probe,NDSA,by combination of DSA with a COX-2-specific ligand indomethacin(IMC).NDSA displays the selective response to COX-2 according to the fluorescence test in vitro,also it can specifically light up Golgi apparatus of cancer cell lines,and the excellent biocompatibility and low cytotoxicity of NDSA make it suitable for cell imaging according to biological test including bioimaging and toxicity test.更多还原