Zhang Jing, Chen Jinghua, Chen Rongchun, Chen Guonan, Fu Fengfu
Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, and Department of Chemistry, Fuzhou University, Fuzhou, Fujian, 350108, China.
Biosens Bioelectron. 2009 Oct 15;25(2):378-82. doi: 10.1016/j.bios.2009.07.029. Epub 2009 Aug 3.
A new electrochemical biosensor for the monitoring of ultratrace terbium based on the conformational change of DNA containing a single guanine (G)-rich stretch was described here. The biosensor was fabricated by immobilizing a thiolated DNA containing a single G-rich stretch on the gold surface as probe surface. The G-rich DNA probe was found to be capable of changing its configuration from flexible single-stranded structures to rigid tetramolecular G-quadruplex in the presence of terbium III, which provided a switchable charge transport path for the oxidation of Fe(CN)(6). The switchable surface provided a sensing platform for the single-step and reagentless detection of Tb(3+). Using this reusable electrochemical sensing platform, a simple, rapid, and selective biosensor for the determination of ultratrace terbium ions with a detection limit of 6.0 x 10(-11)M has been developed. The success in the present biosensor served as a significant step toward the development of monitoring ultratrace Tb(3+) in river water or seawater.
本文描述了一种基于含单个富含鸟嘌呤（G）片段的DNA构象变化来监测超痕量铽的新型电化学生物传感器。该生物传感器通过将含单个富含G片段的硫醇化DNA固定在金表面作为探针表面来制备。发现富含G的DNA探针在铽（III）存在下能够将其构型从柔性单链结构转变为刚性四分子G-四链体，这为[Fe(CN)(6)]4-的氧化提供了可切换的电荷传输路径。该可切换表面为铽（3+）的单步无试剂检测提供了传感平台。利用这个可重复使用的电化学生物传感平台，开发了一种简单、快速且选择性好的生物传感器用于测定超痕量铽离子，检测限为6.0×10-11M。当前生物传感器的成功是朝着监测河水或海水中超痕量铽（3+）发展迈出的重要一步。
