近红外氨基菁染料产生比例双荧光的机理研究

At present, in China diagnostic reagents for major diseases are very lack, most of them rely on imports. Abnormal changes in cellular microenvironmental viscosity are related to cellular aspects of many diseases and malfunctions. The existing living cell fluorescence viscosity probes suffer from some drawbacks such as short excitation and emission wavelength. Besides, the fluorescence intensity of these probes are affected by the probe concentration, etc. Ratiometric dual-fluorescence imaging approaches have been suggested to overcome these problems, which can be used to accurately measure biological viscosity. Fluorescent probes Cy7-NCY and Cy5-NHY could be used to inspect viscosity changes by ratiometric dual-fluorescence imaging. In this project, we will calculate the charge transfer of excitation and emission process and the potential energy curves of the different twisting angle for Cy7-NCY and Cy5-NHY by quantum chemistry calculations. Computational studies reveal the structure characteristics and the mechanism of dual fluorescence in viscous environment for dual fluorescent amino cyanine dyes. On this basis, by adjusting the methylidyne chain and amino groups of amino-substituted cyanine dyes to regulate the electron-donating ability and rotation of the amino, we will prepare a library of new amino-substituted cyanine dyes to probe the dual fluorescent processes and the molecular structure–viscosity sensitivity relationship of amino-substituted cyanine dyes. These theoretical and experimental investigations will be important for the development of novel fluorescent viscosity probe with high photostability, near-infrared and ratiometric dual-fluorescence. The results in this study will show important significance for cells (organization) microenvironment viscosity change law and related disease pathology，diagnostic and applications..

目前，我国对于重大疾病诊断试剂极为缺乏，大部分依赖进口。已报道细胞微环境粘度异常致其功能紊乱与多种人类重大疾病密切相关。现有的活细胞荧光粘度探针激发和发射波长短，荧光信号强度易受到探针浓度等其他因素影响。而染料的比例双荧光现象能够克服这些缺点。Cy7-NCY和Cy5-NHY可用于近红外比例双荧光粘度检测。本项目拟借助于量子化学计算，计算Cy7-NCY和Cy5-NHY的光激发和光发射过程的电荷转移以及沿着不同二面角转动的基态和激发态势能曲线，揭示双荧光氨基菁染料具有的特点以及在粘性环境中产生双荧光现象的机理。在此基础上，调整氨基菁染料甲川链的长短和氨基基团，调控氨基的供电性和转动性，对Cy7和Cy5系列氨基菁染料进行理论预测、合成和光谱性能测试，从而筛选出稳定性能好、近红外、比例双荧光现象明显的氨基菁染料。这些研究将对研究细胞（组织）微环境粘度变化规律和相关疾病的病理、及诊断具有重要意义。

项目致力于精细化工领域染料分子结构与功能创新的研究，集中在新型生物医疗诊断用染料。项目提出通过染料分子激发态调控、分子设计及感应机理方面来提升染料的功能。.1.在生物体系的应用中，具有长波长激发和发射的染料相比于短波长染料具有更好的组织穿透能力、光毒性低、避免对生物样本的损伤等优点。Cy7-NCY和Cy5-NHY染料在粘性环境下表现出近红外和比例双荧光现象。.2.在低粘度溶剂中，氨基可以描述为一个转子，并通过光激发与甲川连不产生耦合，显示出具有长波长的发射峰。相反，在高粘溶液中，氨基几乎与甲川连平行，氨基的孤对电子与甲川链有效重叠，产生耦合，导致波长较短的发射峰。.3.在粘性环境中，取代的氨基和甲川链的旋转能力的总体平衡影响着辐射和非辐射过程的竞争。