发夹式DNA探针检测水中汞

Detection of mercury in water using hairpin DNA probes

利用荧光染料双标记的DNA探针,实现了对水中Hg^(2+)的一步检测。实验中使用的DNA探针是富T结构的发夹式DNA探针链,若水样中不存在Hg^(2+),双标记的DNA探针两端的荧光染料Cy3与Cy5之间的距离很小,会发生荧光能量共振转移,Cy3的荧光发射强度降低;反之,Hg^(2+)会与DNA探针上的T碱基生成T-Hg^(2+)-T的稳定结构,使DNA链结构发生变化,同时Cy3,Cy5之间的距离变大,二者间的能量共振转移减弱甚至消失,Cy3的荧光发射强度回升。因此,通过Hg^(2+)的浓度与Cy3的荧光发射强度的变化的线性关系,可以实现Hg^(2+)的定量检测。

In this paper,a new method for the detection of mercury ion in water by using a double labeled DNA probe was developed. A T-rich hairpin DNA chain was used here to achieve one-step detection of Hg^（2＋）. In the absence of Hg^（2＋）,the fluorescence resonance energy transfer is very strong and the fluorescence emission intensity of Cy3 is reduced,because the distance of Cy3 and Cy5 is less than 10 nm. On the contrary,the Hg^（2＋）can bind T-rich DNA specifically,and a T-Hg^（2＋）-T stable structure is formed in the presence of Hg^（2＋）,which directly weakens the fluorescence energy transfer between Cy3 and Cy5,and the fluorescence emission intensity of Cy3 is recovered. Therefore by analyzing the correlation between the fluorescence emission intensity of Cy3 and the concentration of Hg^（2＋）,quantitative detection of Hg^（2＋）in the unknown water sample was performed.