基于深红/近红外两亲性BODIPY荧光纳米探针的设计、自组装及G-四链体DNA识别应用

G-quadruplex DNA, a new secondary DNA structure, plays important roles as regulatory elements in many biological processes, especially in regulating gene transcription and translation, and then affects cell proliferation and cancer progression. Detection of the quadruplex structures using probes will help to explore the distribution, function, and mechanism of G-quadruplexes in human cells, and may also provide new diagnostic and therapeutic approaches of cancer. While many small-molecule fluorescent probes for G-quadruplex DNA have been developed, there also still exist a lot of problems on selectivity, toxicity and biological compatibility. Recently, fluorescent nano-probes based on self-assembly of organic small molecules have been widely applied in detection of molecules in organisms, early detection of cancer and labeling drug delivery, due to their good selectivity, high sensitivity, better biological compatibility and real-time and in situ detection, etc. This project seeks to design and synthesize a series of far-red/near-infrared fluorescent nano-probes based on self-assembled amphiphilic BODIPY derivates. Tuning the ability of self-assembling and seletive recognition of nano-probes by rational design of their structures. Evaluation on the detection, regulation and intervention of G-quadruplex DNA at the level of cells of these recognition molecules was also investigated. This study will provide valuable data and theory foundation for the design of novel nano-probes for G-quadruplex DNA.

G-四链体DNA是一种特殊的核酸二级结构，涉及端粒维持、基因表达与调控、细胞的增殖和凋等过程。靶向G-四链体DNA识别分子的构建为理解该结构在人类基因中的分布、功能和机制奠定基础，也为解决抗肿瘤靶向性问题提供了一个新的契机。传统小分子荧光探针在识别G-四链体DNA过程中存在选择性不高、毒性大、靶向性及生物兼容性差等问题，限制了进一步应用。近年来，利用分子仿生的理念，通过分子自组装构筑具有特定性质的纳米材料在分子识别、癌细胞早期的发现和干预、药物传递示踪等方面展示出广阔的应用前景。为克服传统有机小分子探针的缺陷，本项目拟构建深红/近红外两亲性氟硼二吡咯荧光纳米探针，调节、优化分子结构以实现自组装行为的调控，提高特异性识别G-四链体DNA的能力。评价探针分子在细胞水平上的检测及调控和干预G-四链体DNA结构与功能的影响。为靶向G-四链体DNA的新型荧光纳米探针分子的构建提供新的思路和方法。

G-四链体是一种特殊的DNA二级结构，与肿瘤的发生与发展等生命过程密切相关。以G-四链体DNA为靶点的识别分子的设计和筛选，对于研究癌症发病机制和开发低毒、高效靶向性抗癌药物具有重要意义。传统小分子荧光探针在识别G四链体DNA过程中存在选择性不高、毒性大、靶向性及生物兼容性差等问题，限制了进一步应用。相比传统的小分子荧光探针，自组装纳米探针在高特异性、灵敏性和生物兼容性等方面都展现出了明显优势。基于此，本项目研究以解决传统小分子荧光探针面临的瓶颈问题为目的，我们首先设计、筛选了不同母环结构的系列G-四链体分子探针，并获得了多个高效识别不同G-四链体结构的探针分子，建立了G-四链体检测方法；初步了解了不同侧链对荧光探针的响应性能、定位和毒性影响的规律。其次，基于上面研究结果，设计、构筑深红/近红外BODIPY两亲性自组装荧光纳米探针，筛选出了具有特异性识别平行构型G-四链体DNA的分子。并研究分子自组装行为，形貌及尺寸等相关参数。最后进一步开展BODIPY分子进行功能化修饰，成功的获得了对特定G-四链体结构（C-MYC）具有高选择的自组装纳米荧光探针分子。本课题研究工作为新型识别分子的设计、筛选、构效关系和性能评价提供新的方法。