基于G-三链体的新型功能化核酸探针的开发及应用研究

The guanine(G)-rich nucleic acid sequence has attracted wide attention due to its special biological functions and secondary structures. They can form functionalized nucleic acid probes by binding with some small molecule ligands. This kind of probes is not only an important tool for revealing the secondary structure and biological function of the G-rich nucleic acid sequence, but also an important signal conversion and output module for constructing label-free biosensors. However, the folding process of G-rich nucleic acid is complicated and most studies of G-rich nucleic acid sequence are focused on the structure of G-quadruplex. Moreover, during their applications in constructing biosensors, such secondary structures have some shortages, such as uncontrollable regulation and long reaction time. Herein, this project will screen small molecular ligands to bind with G-triplex (it has been reported as a novel secondary structure formed by G-rich nucleic acid recently), so that we can obtain stable and functional G-triplex/small molecular ligands probes. We then apply the probes to develop new biosensors for rapid detection of disease markers, and solve above problems. Additionally, this project also devotes to screen small molecule ligands that can distinguish G-triplex and G-quadruplex effectively. It will provide new tools and technical support for revealing the secondary structure and biological function of the G-rich nucleic acid sequence.

富含鸟嘌呤（G）的核酸序列由于其特殊的二级结构和生物学功能引起了科学界的广泛关注。富G核酸序列与小分子配体结合形成的功能化核酸探针，不仅是揭示富G核酸序列二级结构及其生物学功能的重要工具，而且是构建免标记生物传感器重要的信号转换输出模块。目前大多数研究集中于其所形成的G-四链体结构。然而，富G核酸序列折叠过程较为复杂，存在调控难和反应时间过长的问题。本项目拟以一种新的富G核酸二级结构——G-三链体为研究对象，结合G-三链体易调控的优势，通过筛选小分子配体，获得稳定的、功能化的G-三链体核酸探针，并将其用于生物传感器的构建，解决传统G-四链体核酸探针在构建生物传感器过程中遇到的难题，实现疾病标志物的快速检测，为低成本、免标记生物传感器的构建提供新的信号转换输出模块。另外，筛选能有效区分G-三链体和G-四链体的高特异性小分子配体，为揭示富G核酸序列二级结构及其生物学功能提供新的工具和技术支持。

针对目前大多数关于富G核酸序列的研究集中于G-四链体结构，且其折叠过程复杂，存在调控难和反应时间过长的问题。本项目以一种新的富G核酸二级结构——G-三链体为研究对象，结合G-三链体易调控的优势，通过筛选小分子配体，获得1-3种稳定的、功能化的G-三链体核酸探针，并将其用于多种生物传感器的构建，解决了传统G-四链体核酸探针在构建生物传感器过程中遇到的难题，实现疾病标志物的快速检测。研究表明：富G核酸探针loop上的碱基至关重要。可以通过调整loop上的碱基数量和种类，获得折叠时间更短、结合力更强信号更强更稳定的G-三链体探针。本工作为低成本、免标记生物传感器的构建提供新的信号转换输出模块。另外，筛选能有效区分G-三链体和G-四链体的高特异性小分子配体，也为揭示富G核酸序列二级结构及其生物学功能提供新的工具和技术支持。