DNAzyme-Based Plasmonic Nanomachine for Ultrasensitive Selective Surface-Enhanced Raman Scattering Detection of Lead Ions via a Particle-on-a-Film Hot Spot Construction
DNAzyme-Based Plasmonic Nanomachine for Ultrasensitive Selective Surface-Enhanced Raman Scattering Detection of Lead Ions via a Particle-on-a-Film Hot Spot Construction
复制标题
基于 DNAzyme 的等离子体纳米机器，通过薄膜上的粒子热点结构对铅离子进行超灵敏选择性表面增强拉曼散射检测
DOI：
10.1021/ac5038736
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发表时间：
2014-12-02
影响因子：
7.4
通讯作者：
Xu, Shuping
中科院分区：
文献类型：
--
作者：
Fu, Cuicui;Xu, Weiqing;Xu, Shuping
我们提出了一种基于DNA酶连接等离子体纳米机器的高灵敏度和高选择性的表面增强拉曼散射（Sers）检测铅离子的方法。通过由DNAzyme及其底物组成的刚性双链桥连接体构建了膜上金属纳米颗粒结构。这种DNA酶能被铅离子激活并催化底物的断裂作用。因此，DNA的双链结构将变成柔性单链，使连接到DNAzyme末端的金属纳米颗粒落到金属膜表面。由此，在金属纳米颗粒和金属膜之间产生了接近2nm的窄间隙，表现出类似的“热点”效应，并且显著增强了金属膜表面随机分散的拉曼活性分子的信号。通过测量拉曼活性分子的Sers强度的提高，我们实现了Pb2+离子的最低检测浓度为1.0 nM。这种Sers分析方法具有高度的选择性，并且可以通过对相应DNA序列的精确编程而普遍扩展到其他靶标。
We propose a highly sensitive and selective surface-enhanced Raman scattering (SERS) method for determining lead ions based on a DNAzyme-linked plasmonic nanomachine. A metallic nanoparticle-on-a-film structure was built through a rigid double-stranded bridge linker composed of a DNAzyme and its substrate. This DNAzyme could be activated by lead ions and catalyze a fracture action of the substrate. Thus, the double chain structure of DNA would turn into a flexible single strand, making the metal nanoparticles that connected to the terminal of DNAzyme fall to the surface of the metal film. Hereby, a narrow gap close to 2 nm generated between metal nanoparticles and the metal film, exhibiting a similar effect of a "hot spot" and remarkably enhancing the signal of randomly dispersed Raman-active molecules on the surface of metal film. By measuring the improvement of SERS intensity of the Raman-active molecules, we realized the lowest detection concentration of Pb2+ ions to 1.0 nM. This SERS analytical method is highly selective and can be extended universally to other targets via the accurate programming of corresponding DNA sequences.