高灵敏核酸适体结构开关电化学传感器的研究

Aptamer-based structure-switching electrochemical sensors have attracted tremendous attention and emerged as a promising analytical tool for medical diagnostics due to their simplicity in design, one-step signal detection and good capacity of anti-interference in complex sample matrices. Unfortunately, the existing aptamer-based structure-switching electrochemical sensors suffer from a common drawback of relatively low sensitivity, which limits their further application in the determination of low-abundance targets. To overcome the disadvantage above and develop highly sensitive aptamer-based structure-switching electrochemical sensors, this proposal aims to explore novel, effective methods for reducing the background current and amplifying the output signal. Firstly, a novel protocol named "dual-link bind" for the immobilization of double-stranded nucleic acid probe on the modified electrode will be design to restrict the freedom of motion of the nucleic acid probe and thus suppress the background current. Secondly, electrochemical redox cycle will be introduced into the signal transformation system of the aptamer-based structure-switching electrochemical sensors for electro- catalytically amplifying the sensing signal. Then, a synergetic signaling mechanism for higher sensitivity will be developed through the corporation of background current suppression and signal amplification. And lastly, two kinds of aptamer-based structure-switching electrochemical sensors for cocaine and thrombin based on the synergetic signaling mechanism will be constructed and tested respectively. We believe that the synergetic effect of background current suppression and signal amplification will provide an effective route to significantly improve the sensitivity of the aptamer-based structure-switching electrochemical sensors. And we also believe that a simple, highly sensitive electrochemical sensor platform for quick, accurate determination of physiologically active small molecules and disease-related proteins will be successfully developed based on the findings of this proposal.

核酸适体结构开关电化学传感器具有设计简单、一步信号检测、抗干扰能力强、可直接应用于复杂检测体系的优点，在医学诊断领域具有广泛的应用前景而吸引了大量的研究关注。然而，传统核酸适体结构开关电化学传感器普遍存在灵敏度较低的缺陷，限制了其应用潜力的进一步发挥。本项目针对传统核酸适体开关电化学传感器的上述不足，以发展高灵敏核酸适体结构开关电化学传感器为目标，分别从背景电流抑制和信号放大两个途径探索提高传感器灵敏度的新策略。项目提出通过"双链接"核酸探针固定方式制备修饰电极以降低背景电流，采用电催化反应进行信号转换而实现信号放大，并最终形成基于背景电流抑制与信号放大协同作用的高灵敏核酸适体结构开关电化学传感器设计新方法。本项目的实施，有望获得一种构建灵敏度显著增强的核酸适体结构开关电化学传感器的新思路，开发出简便、高灵敏的用于低浓度生理活性小分子和疾病相关蛋白质分子快速准确检测的电化学传感平台。

核酸适体结构开关电化学传感器是目前分析化学研究的前沿和热点，在医学诊断、环境监测及食品安全检测等领域具有广泛的应用前景。本项目针对传统核酸适体结构开关电化学传感器普遍存在的灵敏度较低的缺陷，通过创新核酸适体探针的结构形式、核酸适体探针在电极表面的固定方法以及分子识别的放大信号转换策略，发展了一系列简便、高灵敏，用于检测小分子和重金属离子的核酸适体结构开关电化学传感器。项目主要研究了双链核酸适体探针的结构对置换型核酸适体结构开关电化学传感器性能的影响；提出了错配双链核酸适体的探针结构新形式；发展了烷基硫醇-碳纳米管-核酸适体层层组装制备的、具有低背景电流和电催化信号放大效应的电化学传感界面。项目的研究结果丰富了核酸适体结构开关电化学传感器设计的新原理与新方法，对于发展快速、高灵敏的核酸适体电化学传感器具有启发意义和指导作用。项目执行期间共发表8篇学术论文，其中SCI收录论文7篇，影响因子7.0以上1篇、影响因子4.0以上4篇。以本项目为依托，共有5名硕士研究生接受了系统的科研训练，1名青年教师晋升为副教授。