富含胸腺嘧啶DNA传感探针对水体中Hg2+的检测

Thymine rich-DNA sensing probe for Hg2+ detection

该工作以富含大量胸腺嘧啶（Thymine，T）核酸单链为识别分子，SYBR Green I （SG）为荧光基团，建立了一种简单、灵敏的荧光增强法检测Hg2＋。由于T-Hg2＋-T键的形成，富T单链自我折叠或者两两配对形成双链DNA结构，当溶液中的SG嵌入DNA双链中时，SG荧光强度显著增强。实验结果表明，SG荧光强度随着Hg2＋浓度的增加而增加。在最优实验条件下，SG的荧光强度与Hg2＋的浓度在4．000×10-7~2．000×10-6 mol/L范围内呈线性关系，检出限为3．900×10-8 mol/L。该方法在含5．0％湘江水实际样品中获得的回收率为98．72％~104．5％，因此该传感器可用于实际湘江水样品中Hg2＋的测量。

Mercury is one of the most toxic heavy metals that present in environment. Therefore, a sensitive and se-lective sensing system for mercury detection is highly demanded. This paper described a fluorescent sensor using a label free Hg2＋specific DNA probe（43mer-T18Stem） and an intercalation dye SYBR Green I（SG）. As is known to all, Hg2＋can specifically interact with thymine base to form strong and stable thymine-Hg2＋-thymine （T-Hg2＋-T） com-plexes. This specific T-Hg2＋-T formation affected the hybridization of the Hg2＋specific probe and the intercalation of SG. The proposed sensor showed a linear response in the range of 4.000×10-7~2.000×10-6 mol/L of Hg2＋with a detec-tion limit of 3.900×10-8 mol/L. The sensor revealed good recovery rates from 98.72%to 102.8%, indicating that the sensing system can be utilized for the determination of Hg2＋in real samples.