Department of Chemistry, National Taiwan University , Taipei, 10617, Taiwan.
Anal Chem. 2014 Feb 18;86(4):2065-72. doi: 10.1021/ac4036789. Epub 2014 Feb 4.
Functional logic gates based on lead ions (Pb(2+)) and mercury ions (Hg(2+)) that induce peroxidase-like activities in gold nanoparticles (Au NPs) in the presence of platinum (Pt(4+)) and bismuth ions (Bi(3+)) are presented. The "AND" logic gate is constructed using Pt(4+)/Pb(2+) as the input and the peroxidase-like activity of the Au NPs as the output; this logic gate is denoted as "Pt(4+)/Pb(2+)(AND)-Au NPPOX". When Pt(4+) and Pb(2+) 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 "INHIBIT" logic gate is fabricated by using Bi(3+) and Hg(2+) as the input and the peroxidase-like activity of the Au NPs as the output; this logic gate is denoted as "Bi(3+)/Hg(2+)(INHIBIT)-Au NPPOX". High peroxidase-like activity of Au NPs in the presence of Bi(3+) is a result of the various valence (oxidation) states of Bi(3+) and Au (Au(+)/Au(0)) atoms on the nanoparticle's surface. When Bi(3+) and Hg(2+) coexist, strong Hg-Au amalgamation results in a large decrease in the peroxidase-like activity of the Au NPs. These two probes (Pt(4+)/Pb(2+)(AND)-Au NPPOX and Bi(3+)/Hg(2+)(INHIBIT)-Au NPPOX) allow selective detection of Pb(2+) and Hg(2+) down to nanomolar quantities. The practicality of these two probes has been validated by analysis of Pb(2+) and Hg(2+) 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 Pb(2+) and Hg(2+) in aqueous solution.
基于铅离子（Pb(2+)）和汞离子（Hg(2+)）的功能逻辑门，在存在铂（Pt(4+)）和铋离子（Bi(3+)）的情况下，诱导金纳米粒子（Au NPs）表现出类过氧化物酶活性。“与”逻辑门是使用 Pt(4+)/Pb(2+)作为输入，Au NPs 的类过氧化物酶活性作为输出构建的；这个逻辑门被表示为“Pt(4+)/Pb(2+)(AND)-Au NPPOX”。当 Pt(4+)和 Pb(2+)共存时，强金属亲和相互作用（Pt 和 Pb 原子/离子之间）和金亲和相互作用（Au 和 Pb/Pt 原子/离子之间）导致 Pt 和 Pb 原子/离子显著沉积在 Au NPs 上，从而增强了类过氧化物酶活性。“抑制”逻辑门是使用 Bi(3+)和 Hg(2+)作为输入，Au NPs 的类过氧化物酶活性作为输出构建的；这个逻辑门被表示为“Bi(3+)/Hg(2+)(INHIBIT)-Au NPPOX”。在 Bi(3+)存在下 Au NPs 的高类过氧化物酶活性是由于 Bi(3+)和 Au（Au(+)/Au(0)）原子在纳米粒子表面的各种价态（氧化态）。当 Bi(3+)和 Hg(2+)共存时，强烈的 Hg-Au 汞齐化导致 Au NPs 的类过氧化物酶活性大幅下降。这两个探针（Pt(4+)/Pb(2+)(AND)-Au NPPOX 和 Bi(3+)/Hg(2+)(INHIBIT)-Au NPPOX）允许选择性地检测低至纳摩尔数量的 Pb(2+)和 Hg(2+)。通过对环境水样（自来水、河水和湖水）中 Pb(2+)和 Hg(2+)的分析，验证了这两种探针的实用性。此外，还构建了基于这两种探针的颜色变化（生成红色的 Resorufin 产物）和 O2 气泡生成的集成逻辑电路，允许在水溶液中目视检测 Pb(2+)和 Hg(2+)。
