Ultrasensitive detection of toxic cations through changes in the tunnelling current across films of striped nanoparticles
Ultrasensitive detection of toxic cations through changes in the tunnelling current across films of striped nanoparticles
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DOI：
10.1038/nmat3406
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发表时间：
2012-11-01
期刊：
影响因子：
41.2
通讯作者：
Grzybowski, Bartosz A.
中科院分区：
文献类型：
--
作者：
Cho, Eun Seon;Kim, Jiwon;Grzybowski, Bartosz A.
尽管已经开发了多种方法来检测金属阳离子，但只有少数方法的灵敏度低于1 pM，而且许多方法需要复杂的程序和复杂的设备。在这里，我们描述了一类简单的固态传感器的超灵敏检测重金属阳离子（值得注意的是，一个前所未有的attomolar限制检测CH3Hg+在标准化的解决方案和环境样品），通过改变隧道电流的纳米粒子（NP）的薄膜保护条纹单层的有机配体。传感器也是高度选择性的，因为配体壳组织的纳米粒子。在结合金属阳离子时，近端NP之间的分子桥的电子结构发生变化，隧穿电流增加，并且高导电路径最终渗透整个膜。膜的结构的纳米级异质性拓宽了阳离子结合常数的范围，这导致宽的灵敏度范围（显着地，超过18个数量级的CH3Hg+浓度）。
Although multiple methods have been developed to detect metal cations, only a few offer sensitivities below 1 pM, and many require complicated procedures and sophisticated equipment. Here, we describe a class of simple solid-state sensors for the ultrasensitive detection of heavy-metal cations (notably, an unprecedented attomolar limit for the detection of CH3Hg+ in both standardized solutions and environmental samples) through changes in the tunnelling current across films of nanoparticles (NPs) protected with striped monolayers of organic ligands. The sensors are also highly selective because of the ligand-shell organization of the NPs. On binding of metal cations, the electronic structure of the molecular bridges between proximal NPs changes, the tunnelling current increases and highly conductive paths ultimately percolate the entire film. The nanoscale heterogeneity of the structure of the film broadens the range of the cation-binding constants, which leads to wide sensitivity ranges (remarkably, over 18 orders of magnitude in CH3Hg+ concentration).