Logic Control of Enzyme-Like Gold Nanoparticles for Selective Detection of Lead and Mercury Ions

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• 作者：Chia-Wen Lien ; Yu-Ting Tseng ; Chih-Ching Huang ; Huan-Tsung Chang
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：February 18, 2014
• 年：2014
• 卷：86
• 期：4
• 页码：2065-2072
• 全文大小：424K
• ISSN：1520-6882

文摘

Functional logic gates based on lead ions (Pb²⁺) and mercury ions (Hg²⁺) that induce peroxidase-like activities in gold nanoparticles (Au NPs) in the presence of platinum (Pt⁴⁺) and bismuth ions (Bi³⁺) are presented. The 鈥淎ND鈥?logic gate is constructed using Pt⁴⁺/Pb²⁺ as the input and the peroxidase-like activity of the Au NPs as the output; this logic gate is denoted as 鈥淧t⁴⁺/Pb²⁺(AND)鈥揂u NP_POX鈥? When Pt⁴⁺ and Pb²⁺ coexist, strong metallophilic interactions (between Pt and Pb atoms/ions) and aurophilic interactions (between Au and Pb/Pt atoms/ions) result in significant increases in the deposition of Pt and Pb atoms/ions onto the Au NPs, leading to enhanced peroxidase-like activity. The 鈥淚NHIBIT鈥?logic gate is fabricated by using Bi³⁺ and Hg²⁺ as the input and the peroxidase-like activity of the Au NPs as the output; this logic gate is denoted as 鈥淏i³⁺/Hg²⁺(INHIBIT)鈥揂u NP_POX鈥? High peroxidase-like activity of Au NPs in the presence of Bi³⁺ is a result of the various valence (oxidation) states of Bi³⁺ and Au (Au⁺/Au⁰) atoms on the nanoparticle鈥檚 surface. When Bi³⁺ and Hg²⁺ coexist, strong Hg鈥揂u amalgamation results in a large decrease in the peroxidase-like activity of the Au NPs. These two probes (Pt⁴⁺/Pb²⁺(AND)鈥揂u NP_POX and Bi³⁺/Hg²⁺(INHIBIT)鈥揂u NP_POX) allow selective detection of Pb²⁺ and Hg²⁺ down to nanomolar quantities. The practicality of these two probes has been validated by analysis of Pb²⁺ and Hg²⁺ in environmental water samples (tap water, river water, and lake water). In addition, an integrated logic circuit based on the color change (formation of reddish resorufin product) and generation of O₂ bubbles from these two probes has been constructed, allowing visual detection of Pb²⁺ and Hg²⁺ in aqueous solution.