A G-quadruplex based label-free fluorescent biosensor for lead ion

详细信息	查看全文 | 推荐本文 |

• 作者：Liangqia Guo ; ^{lqguo@fzu.edu.cn} ; Dandan Nie ; Chunyan Qiu ; Qishan Zheng ; Haiyan Wu ; Peirong Ye ; Yanli Hao ; FengFu Fu ; ^{fengfu@fzu.edu.cn} ; Guonan Chen
• 关键词：G-quadruplex ; Fluorescence biosensor ; Lead ion ; N-methyl mesoporphyrin IX ; DNAzyme
• 刊名：Biosensors and Bioelectronics
• 出版年：2012
• 期刊代码：12_09565663
• 类别：ch
• 出版时间：15 May, 2012
• 卷：35
• 期：1
• 页码：123-127
• 文件大小：388 K

摘要

Many Pb²⁺ biosensors based on Pb²⁺-specific RNA-cleaving DNAzyme have been developed in the past years. However, many of them have limited practical use because of high cost (e.g., enzymes), complicated processing and the use of unstable molecules (e.g., RNA). In this study, a novel label-free fluorescent biosensor for Pb²⁺ was proposed based on Pb²⁺-induced allosteric G-quadruplex (PS2.M). In the presence of K⁺, N-methyl mesoporphyrin IX (NMM) could bind to K⁺-stabilized G-quadruplexes, giving rise to high fluorescence. On addition of Pb²⁺, Pb²⁺ competitively binded to K⁺-stabilized G-quadruplexes to form more compact DNA folds. The Pb²⁺-stabilized G-quadruplexes did not bind to NMM, which resulted in fluorescence decrease. This allowed us to utilize PS2.M for quantitative analysis of Pb²⁺ using the NMM-G-quadruplex system by convenient 鈥渕ix-and-detect鈥?protocol. The fluorescence emission ratio (F₀/F) showed a good linear response toward Pb²⁺ over the range from 5.0 nM to 1.0 渭M with a limit of detection of 1.0 nM. This proposed biosensor was simple and cost efficiency in design and in operation with high sensitivity and selectivity. We validated the practicality of this biosensor for the determination of Pb²⁺ in lake water samples.