Xu Nan, Wang Quanbo, Lei Jianping, Liu Lin, Ju Huangxian
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
Talanta. 2015 Jan;132:387-91. doi: 10.1016/j.talanta.2014.09.031. Epub 2014 Sep 28.
The design of a label-free aptamer for separation of recognition sequence from signal reporter is significant to ensure the high-efficiency affinity between aptamer and target. This work develops a label-free triple-helix aptamer (THA) as sensing platform for "signal-on" fluorescent detection of thrombin. THA was composed of aptamer sequence and help DNA 1 (H1), which contained the complementary sequence of hexachloro-fluorescein (HEX) labeled help DNA 2 (H2). The specific recognition event between aptamer and thrombin triggered the dismission of THA to release H1. The released H1 then reacted with the signal probe of H2/graphene oxide (GO) nanocomposite to form H1-H2 duplex, leading to the fluorescence recovery of H2 due to the detachment of H1-H2 duplex from the surface of GO. With employment of THA as a signal transducer and GO as a "superquencher", this method shows a sensitive response to thrombin with a wide concentration range from 5 to 1200 nM. The limit of detection is 1.8 nM (S/N=3) with excellent selectivity. Considering the universality of THA, the proposed aptasensor would provide a platform for homogeneous fluorescent detection of a wide range of analytes.
设计一种用于将识别序列与信号报告分子分离的无标记适体，对于确保适体与靶标的高效亲和力具有重要意义。这项工作开发了一种无标记三螺旋适体（THA）作为传感平台，用于凝血酶的“信号开启”荧光检测。THA由适体序列和辅助DNA 1（H1）组成，H1包含六氯荧光素（HEX）标记的辅助DNA 2（H2）的互补序列。适体与凝血酶之间的特异性识别事件触发THA解离以释放H1。释放的H1然后与H2/氧化石墨烯（GO）纳米复合材料的信号探针反应形成H1-H2双链体，由于H1-H2双链体从GO表面脱离，导致H2的荧光恢复。以THA作为信号转导器和GO作为“超级猝灭剂”，该方法对凝血酶表现出灵敏响应，浓度范围为5至1200 nM。检测限为1.8 nM（S/N=3），具有出色的选择性。考虑到THA的通用性，所提出的适体传感器将为多种分析物的均相荧光检测提供一个平台。
