A catalytic beacon sensor for uranium with parts-per-trillion sensitivity and millionfold selectivity
A catalytic beacon sensor for uranium with parts-per-trillion sensitivity and millionfold selectivity
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DOI：
10.1073/pnas.0607875104
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发表时间：
2007-02-13
影响因子：
11.1
通讯作者：
Lu, Yi
中科院分区：
文献类型：
--
作者：
Liu, Juewen;Brown, Andrea K.;Lu, Yi
在这里，我们报告了一个催化信标传感器的铀酰（UO 22+）的基础上，在体外选择UO 22+特异性DNA酶。该传感器由一条3'端带有猝灭剂的DNA酶链和一条中间带有核糖核苷酸腺苷（rA）、5'端和3'端分别带有荧光团和猝灭剂的DNA底物组成。UO22+的存在导致DNA底物链在rA位置的催化裂解和荧光团的释放，从而显著增加荧光强度。该传感器的检测限为万亿分之11（45 pM），动态范围高达400 nM，选择性超过其他金属离子的100万倍。最具干扰性的金属离子Th（IV）与荧光素荧光团相互作用，导致荧光强度略微增强，表观解离常数约为230 μ M。该传感器可与最灵敏的铀检测分析仪器相媲美，并展示了其在污染土壤样品中检测铀的应用。这项工作表明，简单，成本效益高，便携式金属传感器可以获得类似的灵敏度和选择性更昂贵和复杂的分析仪器。这种传感器将在铀等放射性核素的环境修复中发挥重要作用。
Here, we report a catalytic beacon sensor for uranyl (UO22+) based on an in vitro-selected UO22+-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 cluencher at the 5' and 3' ends, respectively. The of UO22+ presence 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 approximate to 230 mu 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.