Key Laboratory of Functional Polymer Materials, Ministry of Education, Nankai University, Tianjin, 300071, People's Republic of China.
Analyst. 2010 Mar;135(3):545-9. doi: 10.1039/b924014d. Epub 2010 Jan 28.
A highly sensitive and selective Hg(2+) detection method was developed based on the Hg(2+)-mediated formation of split G-quadruplex-hemin DNAzymes. In this method, two label-free oligonucleotides are used. In the presence of Hg(2+), the two oligonucleotides hybridize to each other to form a duplex, in which T-T mismatches are stabilized by T-Hg(2+)-T base pair. As a result, the G-rich sequences of the two oligonucleotides can associate to form a split G-quadruplex, which is able to bind hemin to form the catalytically active G-quadruplex-hemin DNAzymes. This can be reflected by an absorbance increase when monitored in the H(2)O(2)-ABTS (2,2'-azinobis(3-ethylbenzothiazoline)-6-sulfonic acid) reaction system by using UV-vis absorption spectroscopy. This 'turn-on' process allows the detection of aqueous Hg(2+) at concentrations as low as 19 nM using a simple colorimetric technique. With the development of the studies on metal-base pairs, this Hg(2+)-sensing method can be easily extended to the analysis of other metal ions.
基于汞（Ⅱ）介导的分裂 G-四链体-血红素 DNA 酶的形成，开发了一种高灵敏度和选择性的 Hg(2+)检测方法。在该方法中使用了两种无标记的寡核苷酸。在 Hg(2+)存在下，两个寡核苷酸彼此杂交形成双链，其中 T-T 错配由 T-Hg(2+)-T 碱基对稳定。结果，两个寡核苷酸的富含 G 的序列可以缔合形成分裂的 G-四链体，其能够结合血红素以形成催化活性的 G-四链体-血红素 DNA 酶。这可以通过在 H(2)O(2)-ABTS（2,2'-联氮双（3-乙基苯并噻唑啉-6-磺酸））反应系统中使用紫外可见吸收光谱监测时，吸光度增加来反映。这种“开启”过程允许使用简单的比色技术检测低至 19 nM 的水溶液中的 Hg(2+)。随着对金属碱基对的研究的发展，这种 Hg(2+)传感方法可以很容易地扩展到其他金属离子的分析。
