Wu Zai-Sheng, Chen Chen-Rui, Shen Guo-Li, Yu Ru-Qin
State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, PR China.
Biomaterials. 2008 Jun;29(17):2689-96. doi: 10.1016/j.biomaterials.2008.02.024. Epub 2008 Mar 20.
A novel on/off electronic nanoswitch is for the first time described based on the conformational change of DNA sequence possessing a single guanine (G)-rich stretch. Here, a thiolated, amine-containing G-rich DNA sequence is immobilized on the surface of gold electrode by means of facile sulfur-gold chemistry, followed by being labeled with redox-active ferrocene molecules serving as the signaling species. The surface-confined DNA sequence is able to change its configuration between rigid tetramolecular G-quadruplex and flexible single-stranded structures. The large conformational change enables the probes to perform an inchworm like extending-shrinking motion, which is reflected by the fluctuation in current intensity that depends on the electron-transfer distance between the electrode surface and the redox labels. Since potassium ion can specifically bind to G-quadruplex, using this reagentless reusable electrochemical sensing platform, the simple, rapid and selective detection of potassium ion can be accomplished without the use of exogenous reagents. Success in the present electronic nanoswitch is expected to promote the exploitation of functional DNA-based nanosystems.
首次描述了一种基于具有单个富含鸟嘌呤（G）片段的DNA序列构象变化的新型开/关电子纳米开关。在此，通过简便的硫-金化学方法将含硫醇、胺的富含G的DNA序列固定在金电极表面，随后用作为信号分子的氧化还原活性二茂铁分子进行标记。表面受限的DNA序列能够在刚性四分子G-四链体和柔性单链结构之间改变其构型。这种大的构象变化使探针能够进行类似尺蠖的伸展-收缩运动，这通过取决于电极表面与氧化还原标记之间电子转移距离的电流强度波动得以体现。由于钾离子可以特异性结合到G-四链体上，利用这个无需试剂可重复使用的电化学传感平台，无需使用外源试剂即可实现对钾离子简便、快速且选择性的检测。预计当前电子纳米开关的成功将推动基于功能性DNA的纳米系统的开发。
