化学学报 ›› 2014, Vol. 72 ›› Issue (6): 704-708.DOI: 10.6023/A14040247 上一篇    下一篇

研究论文

DNA/银纳米簇荧光探针在检测Pb2+中的应用

蔺超, 宫贺, 范楼珍, 李晓宏   

  1. 北京师范大学化学学院 北京 100875
  • 收稿日期:2014-04-03 出版日期:2014-06-14 发布日期:2014-05-30
  • 通讯作者: 李晓宏 E-mail:lxhxiao@bnu.edu.cn
  • 基金资助:

    项目受国家自然科学基金(No.21073019)和国家自然基金重点项目(No.21233003)资助.

Application of DNA/Ag Nanocluster Fluorescent Probe for the Detection of Pb2+

Lin Chao, Gong He, Fan Louzhen, Li Xiaohong   

  1. College of Chemistry, Beijing Normal University, Beijing 100875
  • Received:2014-04-03 Online:2014-06-14 Published:2014-05-30
  • Supported by:

    Project supported by the Natural Science Foundation of China (No.21073019) and the Major Research Plan of NSFC (No.21233003)

基于DNA/银纳米簇的荧光特性报道了一种简单、灵敏、高选择性的荧光方法检测Pb2+.以茎部为富G结构,环状部分为聚C结构的发夹型DNA为模板合成具有稳定荧光的银纳米簇.当加入Pb2+后,发夹型DNA在Pb2+诱导下形成G-四链体结构,破坏了发夹型DNA的构型,极大地影响了合成银纳米簇的模板结构,导致银纳米簇的荧光强度降低.Pb2+存在和不存在时所产生荧光强度的差异与发夹型DNA的碱基序列和茎部配对碱基数有关.依据这一现象,在优化DNA碱基序列和茎部配对碱基数的基础上,可实现100 μmol/L至100 nmol/L范围内对Pb2+的定量检测,检出限为10 nmol/L.该方法对Pb2+的检测具有较好的选择性,并可应用于实际水样中Pb2+的检测.检测结果与原子吸收光谱进行比对,显示出较好的一致性.

关键词: 发夹型DNA, 银纳米簇, G-四联体, Pb2+

Lead ion (Pb2+) is one of the most toxic forms of heavy metal, which may affect the environment adversely and pose severe risks to human health.Also it usually induces toxic effects in plants and animals, delays physical or mental development in children, and damages nervous, renal and immune systems.Therefore, sensitive and on-site tracking Pb2+ is highly desirable in environmental protection, as well as disease prevention and treatment.In this paper, hairpin-DNA with a poly-C loop and G-rich stem is selected as a template to synthesize DNA/Ag nanocluster: Ag+ firstly binds with C in the poly-C loop of hairpin DNA, and then is reduced by NaBH4 to form highly fluorescent hairpin DNA/Ag nanocluster.However, in the presence of Pb2+, Pb2+ induces hairpin DNA transforming into Pb2+-stabilized G-quadruplex with the structure of hairpin DNA destroyed, and the synthesized DNA/Ag nanoclusters presented a greatly decreased fluorescence.Importantly, the fluorescence changes of Ag nanoclusters in the absence and presence of Pb2+ are largely dependent on sequences of hairpin DNA and the number of complementary bases appearing in stem portion (six base pairs are optimized).Based on the difference in fluorescent intensity of DNA/Ag nanoclusters (in the absence and presence of Pb2+), Pb2+ could be quantitatively detected with the concentration ranged from 100 μmol/L to 100 nmol/L.The detection limit is 10 nmol/L.This assay is selective for Pb2+ and successfully applied to detect Pb2+ in real water sample.The result of the fluorescent assay for Pb2+ is highly consistent with that of atomic absorption spectroscopy, which presented that the fluorescent assay is reliable.As a result, a simple and sensitive fluorescent assay based on DNA/Ag nanoclusters is developed for the detection of Pb2+, which provides a potential application for Pb2+ detection in the real samples.

Key words: Hairpin DNA, Ag nanoclusters, G-quadruplex, Pb2+