Optical analysis of Hg2+ ions by oligonucleotide-gold-nanoparticle hybrids and DNA-based machines
Optical analysis of Hg2+ ions by oligonucleotide-gold-nanoparticle hybrids and DNA-based machines
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DOI：
10.1002/anie.200705991
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发表时间：
2008-01-01
影响因子：
16.6
通讯作者：
Willner, Itamar
中科院分区：
文献类型：
--
作者：
Li, Di;Wieckowska, Agnieszka;Willner, Itamar
汞离子是一种严重的环境污染物，具有严重的医学效应。[1]具体而言，汞离子（Hg 2+）的微生物生物甲基化产生甲基汞，通过食物链在体内积累，已知会导致脑损伤和其他慢性疾病。[2]此外，在牙齿护理过程中，控制汞合金填充物中Hg 2+离子的泄漏也很重要。[3]因此，快速和灵敏地分析水或食物资源中的Hg 2+离子是重要的，[4]并且分析体液中的Hg 2+离子，例如，唾液具有相当大的诊断价值。开发了不同的Hg 2+离子分析方法，包括电化学方法，[5]包括Hg 2+敏感荧光团或发色团的光学方法，[6]以及使用蛋白质[7]和功能聚合物材料。[8]金属纳米颗粒和半导体量子点[9]已被应用于Hg 2+离子的分析。金属离子与核苷酸嘌呤和嘧啶碱基的络合吸引了最近的研究工作，[10]并且Hg 2 +-双-胸腺嘧啶络合物的形成[11]得到了很好的建立。事实上，近年来开发了各种基于DNA中Hg 2 +-胸腺嘧啶复合物的Hg 2+离子检测分析。富含胸腺嘧啶（T）的核酸被间隔区隔开，并在其末端与荧光团/猝灭剂单元连接，用于通过离子诱导形成发夹结构来分析Hg 2+离子，该发夹结构产生分子内荧光共振能量转移（FRET）过程。[12]共轭聚合物与富含T的核酸的相互作用，这些核酸通过Hg 2+离子以发夹结构的形式自组织，导致通过相应的聚合物-DNA复合物对Hg 2+离子的荧光检测。[13]在聚腺嘌呤（poly-A）存在下，聚-T-官能化的金纳米颗粒（AuNPs）与单-T-多聚体官能化的AuNPs聚集。由此产生的聚集体的熔融温度，并因此，红-蓝光学转变，被发现是由Hg 2+离子的浓度控制; Hg 2+离子的存在下，导致形成颗粒间T-Hg 2 +-T复合物。[14]最近，变构Hg ~（2+）诱导的UO_2 ~（2+）离子依赖性DNA酶的激活被用于Hg ~（2+）的荧光放大检测。[15]在这里，我们描述了两种不同的光学方法来分析Hg 2+离子的基础上形成的Hg 2 +-双-胸腺嘧啶复合物。这些方法是：1）使用聚集的AuNPs分析Hg 2 +; 2）使用基于DNA的机器分析Hg 2+离子。发现单链核酸与金纳米颗粒相互作用，导致寡核苷酸的解螺旋和核苷酸碱基与纳米颗粒的缔合。这稳定了NP在高离子强度条件下的聚集。[16个]
Mercury ions act as severe environmental pollutants and they have serious medical effects.[1] Specifically, microbial biomethylation of mercuric ions (Hg2+) yields methyl mercury that accumulates in the body through the food chain, and is known to cause brain damage and other chronic diseases.[2] Also, it is important to control the leakage of Hg2+ ions from amalgam fillings in teeth during dental care.[3] Hence, the rapid and sensitive analysis of Hg2+ ions in water or food resources is important,[4] and the analysis of Hg2+ ions in human fluids, for example, saliva has considerable diagnostic value. Different procedures for the analysis of Hg2+ ions were developed, including electrochemical methods,[5] optical methods that include Hg2+-sensitive fluorophores or chromophores,[6] and the use of proteins [7] and functional polymer materials.[8] Metal nanoparticles and semiconductor quantum dots [9] have been applied for the analysis of Hg2+ ions. The complexation of metal ions with nucleotide purine and pyrimidine bases attracted recent research efforts,[10] and the formation of Hg2+-bis-thymine complexes [11] is well established. Indeed, various Hg2+ ion detection assays based on the Hg2+-thymine complexes in DNA were developed in the recent years. Thymine (T)-rich nucleic acids separated by a spacer and tethered at their ends with fluorophore/quencher units were used to analyze Hg2+ ions by the ion-induced formation of a hairpin structure that yields an intramolecular fluorescence resonance energy transfer (FRET) process.[12] The interaction of conjugated polymers with T-rich nucleic acids that are selforganized in the form of a hairpin structure by Hg2+ ions led to the fluorescence detection of Hg2+ ions by the respective polymer–DNA complexes.[13] Poly-T-functionalized gold nanoparticles (AuNPs) were aggregated with single-T-mutant-functionalized AuNPs in the presence of polyadenine (poly-A). The melting temperature of the resulting aggregate, and as a result, the red-to-blue optical transition, were found to be controlled by the concentration of Hg2+ ions; the presence of the Hg2+ ions causes a the formation of interparticle T-Hg2+-T complexes.[14] Recently, the allostericHg2+-induced activation of a UO2 2+-ion-dependent DNA-zyme was used for the amplified detection of Hg2+ by fluorescence.[15] Herein we describe two different optical methods to analyze Hg2+ ions that are based on the formation of a Hg2+-bis-thymine complex. These methods are: 1) The analysis of Hg2+ using aggregated AuNPs; 2) The analysis of Hg2+ ions using a DNA-based machine. Single-stranded nucleic acids were found to interact with AuNPs, resulting in the uncoiling of the oligonucleotides and the association of the nucleotide bases to the NPs. This stabilizes the NPs against aggregation under high ionic strength conditions.[16]