Laboratory of Biosensing Technology, School of Life Sciences, Shanghai University, Shanghai 200444, PR China.
Biosens Bioelectron. 2013 Jan 15;39(1):183-6. doi: 10.1016/j.bios.2012.07.073. Epub 2012 Aug 8.
Ag(+) ions are greatly toxic to a lot of algae, fungi, viruses and bacteria, which can also induce harmful side-effects to environments and human health. Herein we report an ultra-sensitive method for the selective detection of Ag(+) ions with electrochemical technique based on Ag(+)-assisted isothermal exponential degradation reaction. In the presence of Ag(+), mismatched trigger DNA can transiently bind to template DNA immobilized on an electrode surface through the formation of C-Ag(+)-C base pair, which then initiates the isothermal exponential degradation reaction. As a result, the mismatched trigger DNA may melt off the cleaved template DNA to trigger rounds of elongation and cutting. After the cyclic degradation reactions, removal of the template DNA immobilized on the electrode surface can be efficiently monitored by using electrochemical technique to show the status of the electrode surface, which can be then used to determine the presence of Ag(+). Further studies reveal that the proposed method can be ultra-sensitive to detect Ag(+) at a picomolar level. The selectivity of the detection can also be satisfactory, thus the proposed method for the Ag(+) ions detection may be potentially useful in the future.
银（Ag(+)）离子对许多藻类、真菌、病毒和细菌有很大的毒性，同时也会对环境和人类健康产生有害的副作用。在此，我们报道了一种基于 Ag(+)-辅助等温指数降解反应的电化学技术，用于选择性检测 Ag(+)离子的超灵敏方法。在 Ag(+)存在的情况下，不匹配的触发 DNA 可以通过形成 C-Ag(+)-C 碱基对，瞬时与固定在电极表面的模板 DNA 结合，从而引发等温指数降解反应。结果，不匹配的触发 DNA 可能会从被切割的模板 DNA 上脱落，从而引发几轮延伸和切割。在循环降解反应后，可以通过电化学技术有效地监测固定在电极表面的模板 DNA 的去除，以显示电极表面的状态，从而用于确定 Ag(+)的存在。进一步的研究表明，该方法可以超灵敏地检测皮摩尔级别的 Ag(+)。检测的选择性也令人满意，因此，该方法可能在未来对 Ag(+)离子的检测具有潜在的应用价值。
