Mercury (Hg) and its compounds, originating from a variety of natural and anthropogenic sources, are ubiquitous in the natural environment, and cause severe environmental contamination and pose irreversible harm to human health. A fast and accurate sensing approach is of significant importance for mercury detection. Here, a label-free biosensor using Hg(II)-induced cleavage of phosphorothioate (PS) modified RNA was exploited. We designed a specific single-stranded DNA embedded with four PS-modified RNA (Hg-DPR) to improve the cleavage reaction yield, and then Hg-DPR was covalently linked with single-walled carbon nanotube field effect transistor (SWNTs/FET) via a peptide bond. The Hg-DPR can be efficiently cleaved after exposure to Hg(II), which further causes the conductivity of the SWNTs to change. Using the relative resistance change, the Hg-DPR/SWNTs/FET successfully detected Hg(II) levels as low as 10 pM, and the calibration curves were linear in the range of 50 pM to 100 nM and 100 nM to 10 μM. Additionally, Hg-DPR/SWNTs/FET exhibited excellent sensitivity, portability, and low-cost for Hg(II) detection.

中文翻译：

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DNA嵌入硫代磷酸酯修饰的RNA的电化学生物传感器用于汞离子的测定

汞（Hg）及其化合物源自多种自然和人为来源，在自然环境中无处不在，会造成严重的环境污染，并对人类健康造成不可逆转的危害。快速准确的感测方法对于汞检测非常重要。在这里，开发了一种无标记的生物传感器，该传感器使用Hg（II）诱导的硫代磷酸酯（PS）修饰的RNA裂解。我们设计了嵌入四个PS修饰的RNA（Hg-DPR）的特定单链DNA，以提高裂解反应的产率，然后Hg-DPR通过以下方式与单壁碳纳米管场效应晶体管（SWNTs / FET）共价连接：肽键。暴露于Hg（II）后，Hg-DPR可以有效裂解，这进一步导致SWNT的电导率发生变化。利用相对电阻变化，Hg-DPR / SWNTs / FET成功检测到低至10 pM的Hg（II）水平，并且校准曲线在50 pM至100 nM和100 nM至10μM范围内呈线性。此外，Hg-DPR / SWNTs / FET对Hg（II）的检测具有出色的灵敏度，便携性和低成本。