基于铅(Ⅱ)-G-四联体功能核酸非标记荧光传感检测氡的新方法研究

Radon is a radioactive and carcinogenic pollutant which widely exists in people's life and work environment, hence it is of great significance to establish a new method to detect radon with high sensitivity and accuracy. Radon radiates alpha, beta ray and decays quickly into stable progeny lead. Until now, the detecting methods for radon have aimed generally at ray. In this subject on the basis of the latest biological detection technology of Pb2+, a new method for radon measurement will be established based on lead. Pb2+ ion (pM level) can be detected highly selectively as lead(II) induces a guanine(G)-rich oligonucleotide to change into lead(Ⅱ)-stabilized G-quadruplex formation and couples the changes of fluorescent output signal. Label-free fluorescent sensing technology of G4-Pb2+ functional nucleic acid is of high sensitivity and better selectivity. In this subject, a guanine (G)-rich DNA will be synthesized and screened, a label-free fluorescent DNA sensor for the detection of Pb2+ will be constructed by implying a guanine (G)-rich DNA as the probe and SYBR Green(SG) as the signal reporter. SG is an intercalator and exhibits a high fluorescence when intercalated with DNA. The progeny lead of radon is collected by nitric acid and changed into lead ion. And the fluorescence will quench in the system because Pb2+ induces rich-G dsDNA to transform into G4-Pb2+ and concentration of the dsDNA can be decreased. The label-free fluorescent sensing novel method will be established for the detection of radon based on lead(Ⅱ)-stabilized G-quadruplex formation of function nucleic acids. It has some peculiar characteristics such as label-free fluorescent, low cost, measurement in the common temperature and signal stability. The bottlenecks of the original method can be broken through. Moreover, mechanism through which randon radiation makes dsDNA structure change will also be discussed. With the study on this project, we can provide new research ideas for DNA radiation damage.

氡是放射性致癌污染物，广泛存在人们生活工作环境中，建立灵敏准确的检测新方法具有重要意义。氡辐射α、β射线，很快衰变成最稳定的子体铅，目前普遍针对射线监测氡。本课题依据Pb2+的最新生物检测技术，建立基于铅检测氡的新方法：Pb2+特异性诱导富G dsDNA形成稳定的 G4-Pb2+四联体，输出信号变化，可高选择性检测pM级Pb2+。非标记G4-Pb2+功能核酸荧光传感技术更加灵敏，选择性更好。本课题筛选合成荧光探针富G dsDNA，以DNA嵌入剂SG为荧光信使，SG与dsDNA结合产生强荧光。用硝酸采集氡子体铅，形成的Pb2+诱导富GdsDNA转型为G4-Pb2+，dsDNA减少，荧光猝灭，据此构建氡的G4-Pb2+功能核酸非标记荧光传感检测新方法。新方法DNA无荧光标记、成本低、可常温测定、信号稳定，突破了原方法的瓶颈。并将探讨氡辐射使dsDNA结构变化的机理，为DNA辐射损伤提供新思路。

2014年国家自然科学基金委批准面上项目"基于铅(Ⅱ)-G-四联体功能核酸非标记荧光传感检测氡的新方法研究"，项目批准号： 81473021。.按照课题设计方案，顺利地执行了课题“氡子体210Pb的化学采样研究”工作计划、“基于铅(Ⅱ)-G-四联体功能核酸非标记荧光传感检测氡的新方法研究”两大研究内容，达到了相应的研究目标，解决了关键科学问题，取得了预期的研究成果。“特色与创新”比较突出，取得了课题的预期研究成果。.首次构建了一种全新的氡的化学采样装置，阐述了其采样原理。与目前全世界普遍使用的氡物理检测采样方法相比较，新装置、新方法具有原始创新性、具有简便、安全、经济多种优势；并应用现代先进检测技术ICP/MS对照研究了采样新方法的科学性。.编排、筛选了多种富GDNA序列，优选了多种生物染料，共构建了20种氡的荧光传感生物分析新方法。.在美国ACA等学术期刊公开发表了12篇学术论文，SCI收录6篇；在投国际学术论文2篇；完成硕士学位论文5篇，正在撰写硕士学位论文2篇。主编出版专著1部；参与编写百科全书1部。申请并被受理专利2项。指导获批相关研究的省级研究生、本科生创新课题三项。培养硕士研究生毕业6人、在读4人；指导11名本科生毕业论文。.本项目显示多方面的学术价值：.在放射性物质氡的研究领域中，创建了基于子体铅的氡化学研究新思路，实现了理论突破。本课题研究成果突破了“（铀→）氡→α、β、γ 射线”的核物理研究框框，开启“（铀→）氡→铅→基因突变”的研究新思路，开发一种“DNA辐射损伤机理研究”的生物物理新方法，在核素检测领域具有实际应用前景；在核素辐射基因损伤研究领域中具有应用拓展价值。.创建了针对子体铅的氡化学采样研究思路，实现了对氡的无辐射损伤采样，实现了氡累积浓度简便、灵敏、稳定、安全的采样、检测目标。.创建了针对子体铅的氡检测全新研究思路，创建了放射性氡累积浓度的20种核酸适配体生物荧光传感检测新方法。.开拓了核酸适配体检测放射性、非金属、气态物质的新领域。