A test strip platform based on DNA-functionalized gold nanoparticles for on-site detection of mercury (II) ions

详细信息	查看全文 | 推荐本文 |

• 作者：Zhiyong Guo ; ^{nbuguo@163.com} ; Jing Duan ; Fei Yang ; Min Li ; Tingting Hao ; Sui Wang ; Danyi Wei
• 关键词：Mercury (II) ion ; Gold nanoparticles ; DNA ; Test strip
• 刊名：Talanta
• 出版年：2012
• 期刊代码：106_00399140
• 类别：ch
• 出版时间：15 May, 2012
• 卷：93
• 期：Complete
• 页码：49-54
• 文件大小：685 K

摘要

A test strip, based on DNA-functionalized gold nanoparticles for Hg²⁺ detection, has been developed, optimized and validated. The developed colorimetric mercury sensor system exhibited a highly sensitive and selective response to mercury. The measurement principle is based on thymineHg²⁺thymine (THg²⁺T) coordination chemistry and streptavidin-biotin interaction. A biotin-labeled and thiolated DNA was immobilized on the gold nanoparticles (AuNPs) surface through a self-assembling method. Another thymine-rich DNA, which was introduced to form DNA duplexes on the AuNPs surface with thymineHg²⁺thymine (THg²⁺T) coordination in the presence of Hg²⁺, was immobilized on the nitrocellulose membrane as the test zone. When Hg²⁺ ions were introduced into this system, they induced the two strands of DNA to intertwist by forming THg²⁺T bonds resulting in a red line at the test zone. The biotin-labeled and thiolated DNA-functionalized AuNPs could be captured by streptavidin which was immobilized on the nitrocellulose membrane as the control zone. Under optimized conditions, the detection limit for Hg²⁺ was 3 nM, which is lower than the 10 nM, maximum contaminant limit defined by the US Environmental Protection Agency (EPA) for drinking water. A parallel analysis of Hg²⁺ in pool water samples using cold vapor atomic absorption spectrometry showed comparable results to those obtained from the strip test. Therefore, the results obtained in this study could be used as basic research for the development of Hg²⁺ detection, and the method developed could be a potential on-site screening tool for the rapid detection of Hg²⁺ in different water samples without special instrumentation. All experimental variables that influence the test strip response were optimized and reported.