DNAzyme-Based Plasmonic Nanomachine for Ultrasensitive Selective Surface-Enhanced Raman Scattering Detection of Lead Ions via a Particle-on-a-Film Hot Spot Construction

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• 作者：Cuicui Fu ; Weiqing Xu ; Hailong Wang ; Han Ding ; Lijia Liang ; Ming Cong ; Shuping Xu
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：December 2, 2014
• 年：2014
• 卷：86
• 期：23
• 页码：11494-11497
• 全文大小：281K
• ISSN：1520-6882

文摘

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 鈥渉ot spot鈥?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.