Ultrasensitive, Specific, Recyclable, and Reproducible Detection of Lead Ions in Real Systems through a Polyadenine-Assisted, Surface-Enhanced Raman Scattering Silicon Chip

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• 作者：Yu Shi ; Houyu Wang ; Xiangxu Jiang ; Bin Sun ; Bin Song ; Yuanyuan Su ; Yao He
• 刊名：Analytical Chemistry
• 出版年：2016
• 出版时间：April 5, 2016
• 年：2016
• 卷：88
• 期：7
• 页码：3723-3729
• 全文大小：516K
• ISSN：1520-6882

文摘

It is of great significance to accurately and reliably detect trace lead(II) (Pb²⁺) ions, preferably at sub-nM level due to the possible long-term accumulation of Pb²⁺ in the human body, which may cause serious threats to human health. However, a suitable Pb²⁺ sensor meeting the demands is still scanty. Herein, we develop a polyadenine-assisted, surface-enhanced Raman scattering (SERS) silicon chip (0.5 cm × 0.5 cm) composed of core (Ag)-satellite (Au) nanoparticles (Ag–Au NPs)-decorated silicon wafers (Ag–Au NPs@Si) for high-performance Pb²⁺ detection. Typically, strong SERS signals could be measured when DNAzyme conjugated on the SERS silicon chip is specifically activated by Pb²⁺, cleaving the substrate strand into two free DNA strands. A good linearity exists between the normalized Raman intensities and the logarithmic concentrations of Pb²⁺ ranging from 10 pM to 1 μM with a good correlation coefficient, R² of 0.997. Remarkably, Pb²⁺ ions with a low concentration of 8.9 × 10^–12 M can be readily determined via the SERS silicon chip ascribed to its superior SERS enhancement, much lower than those (∼nM) reported by other SERS sensors. Additionally, the developed chip features good selectivity and recyclability (e.g., ∼11.1% loss of Raman intensity after three cycles). More importantly, the as-prepared chip can be used for accurate and reliable determination of unknown Pb²⁺ ions in real systems including lake water, tap water and industrial wastewater, with the RSD value less than 12%.