文章基本信息

标题：A catalytic beacon sensor for uranium with parts-per-trillion sensitivity and millionfold selectivity
本地全文：下载
作者：Juewen Liu ; Andrea K. Brown ; Xiangli Meng 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2007
卷号：104
期号：7
页码：2056-2061
DOI：10.1073/pnas.0607875104
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Here, we report a catalytic beacon sensor for uranyl (UO[IMG]f1.gif" ALT="Formula" BORDER="0">) based on an in vitro-selected UO[IMG]f1.gif" ALT="Formula" BORDER="0">-specific DNAzyme. The sensor consists of a DNA enzyme strand with a 3' quencher and a DNA substrate with a ribonucleotide adenosine (rA) in the middle and a fluorophore and a quencher at the 5' and 3' ends, respectively. The presence of UO[IMG]f1.gif" ALT="Formula" BORDER="0"> causes catalytic cleavage of the DNA substrate strand at the rA position and release of the fluorophore and thus dramatic increase of fluorescence intensity. The sensor has a detection limit of 11 parts per trillion (45 pM), a dynamic range up to 400 nM, and selectivity of >1-million-fold over other metal ions. The most interfering metal ion, Th(IV), interacts with the fluorescein fluorophore, causing slightly enhanced fluorescence intensity, with an apparent dissociation constant of {approx}230 {micro}M. This sensor rivals the most sensitive analytical instruments for uranium detection, and its application in detecting uranium in contaminated soil samples is also demonstrated. This work shows that simple, cost-effective, and portable metal sensors can be obtained with similar sensitivity and selectivity as much more expensive and sophisticated analytical instruments. Such a sensor will play an important role in environmental remediation of radionuclides such as uranium.
关键词：DNA ; DNAzyme ; fluorescence ; deoxyribozyme ; catalytic DNA