Highly sensitive detection of mercury(II) ions by fluorescence polarization enhanced by gold nanoparticles.
Highly sensitive detection of mercury(II) ions by fluorescence polarization enhanced by gold nanoparticles.
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DOI：
10.1002/anie.200803069
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发表时间：
2008-10
影响因子：
--
通讯作者：
B. Ye;Bincheng Yin
中科院分区：
文献类型：
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作者：
B. Ye;Bincheng Yin
几十年来，重金属离子对环境的污染一直是全球关注的重要问题。汞可以在重要器官和组织中积累，如肝脏，大脑和心肌，具有高度毒性，对生命系统具有致命影响。汞主要来自燃煤发电厂、海洋和火山排放、金矿开采和废物燃烧。汞离子的微生物生物甲基化作用产生甲基汞，这是一种强有力的神经毒素，通过食物链进入鱼类和海洋哺乳动物的组织。因此，非常需要开发一种灵敏的和选择性的汞检测方法，该方法可以提供简单、实用和高通量的环境和食品样品中汞离子水平的常规测定。汞离子传感系统的设计已经投入了大量的精力，包括基于有机发色团或荧光团、共轭聚合物、DNA酶、金纳米颗粒、半导体量子点、蛋白质和基因工程细菌的传感器。然而，这些方法中的大多数具有一些局限性，例如选择性差，受到密切相关金属的干扰，灵敏度不足（检测限（LOD）> 100 nm），并且在某些情况下在水性介质中不稳定或不起作用（因为水溶性低）。另一种新出现的汞离子检测方法涉及使用寡核苷酸。汞离子能特异性地与胸腺嘧啶碱基相互作用，形成稳定的胸腺嘧啶-汞-胸腺嘧啶复合物（T-Hg-T）。近年来，基于T-Hg-T配位化学的这一性质，已经开发了各种Hg离子检测分析。Ono和Togashi描述了一种基于Hg诱导的DNA折叠的简单方法，该方法产生分子内荧光共振能量转移过程，并允许以高选择性和灵敏度（高达40 nm）检测Hg离子。Mirkin及其同事最近报道了使用具有专门设计的T-T错配的DNA功能化金纳米粒子（AuNP）探针在水介质中比色检测Hg离子，灵敏度高达100 nm。此外，Liu及其同事开发了一种一步，室温下，使用灵敏度为1 mm的DNA-纳米颗粒结合物的汞离子比色测定法。根据美国环境保护署（EPA）标准，饮用水中汞离子的最大允许水平（MAL）为10 nm（2.0 ppb）。该浓度远低于大多数可用测定的检测限。因此，开发一种高灵敏度、简便实用的汞离子检测方法仍然是一个挑战。本文提出了一种基于T-Hg-T复合物形成的高灵敏度、高选择性的荧光偏振分析（FPA）方法。检测灵敏度可以显着提高到0.2 ppb（1.0 nm），通过使用“金纳米粒子增强”的方法。金纳米粒子（AuNP）增强功能已被用于显著提高各种生物传感系统的性能和灵敏度。通过使用金纳米颗粒作为放大石英晶体微天平检测和电化学检测的标记物，通过应用金纳米颗粒作为电子继电器促进电极上的界面电子转移，实现了增强的效果。最近，还报道了AuNP在响应性聚合物凝胶和网络场效应晶体管中的增强效应。荧光偏振值P对荧光标记分子的旋转运动的变化敏感。它可以通过Perrin方程[Eq. (1)]其中t是荧光寿命，h是粘度
Contamination of the environment with heavy metal ions has been an important worldwide concern for decades. Mercury, which can accumulate in vital organs and tissues, such as the liver, brain, and heart muscle, is highly toxic and can have lethal effects on living systems. Mercury originates mainly from coal-burning power plants, oceanic and volcanic emissions, gold mining, and waste combustion. Futhermore, microbial biomethylation of Hg ions yields methyl mercury, a potent neurotoxin that passes through the food chain to the tissues of fish and marine mammals. Therefore, it is highly desirable to develop a sensitive and selective mercury detection method that can provide simple, practical, and high-throughput routine determination of levels of Hg ions for both environmental and food samples. Much effort has been devoted towards the design of sensing systems for Hg ions, including sensors based on organic chromophores or fluorophores, conjugated polymers, DNAzymes, gold nanoparticles, semiconductor quantum dots, proteins, and genetically engineered bacteria. However, most of these methods have some limitations such as poor selectivity with interference from closely related metals, insufficient sensitivity (limit of detection (LOD)> 100 nm), and in certain cases are nonstable or nonfunctional in aqueous media (because of low water solubility). Another emerging approach for the detection of Hg ions involves the use of oligonucleotides. Hg ions can specifically interact with thymine bases to form strong and stable thymine–Hg–thymine complexes (T–Hg–T). Various Hg ion detection assays based on this property of T– Hg–T coordination chemistry have been developed in recent years. Ono and Togashi have described a simple method based on Hg-induced DNA folding, which yields an intramolecular fluorescence resonance energy transfer process and allows the detection of Hg ions with high selectivity and sensitivity (up to 40 nm). Mirkin and co-workers recently reported the colorimetric detection of Hg ions in aqueous media using DNA-functionalized gold nanoparticle (AuNP) probes with specifically designed T–T mismatches with a sensitivity of up to 100 nm. Furthermore, Liu and coworkers developed an one-step, room temperature, colorimetric assay of Hg ions using DNA–nanoparticle conjugates with a sensitivity of 1 mm. According to the US Environmental Protection Agency (EPA) standard, the MAL (maximum allowable level) of Hg ions in drinking water is 10 nm (2.0 parts per billion (ppb)). This concentration is much lower than the detection limit of most available assays. Thus, the development of a highly sensitive, facile, and practical assay for Hg ions remains a challenge. Herein, we present a novel highly sensitive and selective fluorescence polarization assay (FPA) method for the detection of Hg ions on the basis of the formation of T–Hg–T complexes. The detection sensitivity can be significantly improved to 0.2 ppb (1.0 nm) by using a “gold nanoparticle enhancement” approach. Gold nanoparticle (AuNP) enhancement functions have been employed to substantially improve the performance and sensitivity of various biosensing systems. The enhanced effects were implemented by the use of AuNPs as labels for amplified quartz crystal microbalance detection and electrochemical detection, by the application of AuNPs as electron relays for the facilitation of interfacial electron transfer on electrodes. Recently, AuNP-enhanced effects in a responsive polymer gel and in network field-effect transistors were also reported. The fluorescence polarization value P is sensitive to changes in the rotational motion of fluorescently labeled molecules. It can be calculated by the Perrin equation [Eq. (1)], where t is the fluorescence lifetime, h is the viscosity