Electrolyte-free Amperometric Immunosensor using a Dendritic Nanotip.
Electrolyte-free Amperometric Immunosensor using a Dendritic Nanotip.
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DOI：
10.1039/c3ra40262b
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发表时间：
2013
期刊：
影响因子：
3.9
通讯作者：
Chung JH
中科院分区：
文献类型：
--
作者：
Kim JH;Hiraiwa M;Lee HB;Lee KH;Cangelosi GA;Chung JH
使用纳米组件的电检测可能会导致快速和简单的生物传感平台。由纳米尖端或纳米点组成的传感器已经被描述用于通过受限几何形状实现的高灵敏度电流分析法。然而，纳米结构传感器的制造和使用仍然具有挑战性。本文介绍了一种树枝状纳米针尖作为电流型生物传感器用于高灵敏度检测目标细菌。树枝状纳米尖端是由硅纳米线与单壁碳纳米管（SWCNTs）的高电场产生的涂层结构。为了使用树枝状结构进行可靠的测量，通过紫外（UV）光刻和蚀刻均匀地制造Si纳米线。根据数值计算，树枝状结构有效地增加了纳米尖端末端附近的电流密度。采用循环伏安法和I-V测试法研究了带有蛋白质层的树枝状纳米针尖在去离子水中的电学特性。当被扩散捕获到纳米尖端上的目标细菌与荧光抗体结合时，通过去离子水的电流降低。测量结果与荧光显微镜和电子显微镜一致。电流分析法的灵敏度为10 cfu/样品体积（103 cfu/mL），相当于更费力的荧光测量方法。树枝状纳米尖端的简单配置可能为灵敏和快速的生物传感器提供无电解质的检测平台。
Electric detection using a nanocomponent may lead to platforms for rapid and simple biosensing. Sensors composed of nanotips or nanodots have been described for highly sensitive amperometry enabled by confined geometry. However, both fabrication and use of nanostructured sensors remain challenging. This paper describes a dendritic nanotip used as an amperometric biosensor for highly sensitive detection of target bacteria. A dendritic nanotip is structured by Si nanowires coated with single-walled carbon nanotubes (SWCNTs) for generation of a high electric field. For reliable measurement using the dendritic structure, Si nanowires were uniformly fabricated by ultraviolet (UV) lithography and etching. The dendritic structure effectively increased the electric current density near the terminal end of the nanotip according to numerical computation. The electrical characteristics of a dendritic nanotip with additional protein layers was studied by cyclic voltammetry and I–V measurement in deionized (DI) water. When the target bacteria dielectrophoretically captured onto a nanotip were bound with fluorescence antibodies, the electric current through DI water decreased. Measurement results were consistent with fluorescence- and electron microscopy. The sensitivity of the amperometry was 10 cfu/sample volume (103 cfu/mL), which was equivalent to the more laborious fluorescence measurement method. The simple configuration of a dendritic nanotip can potentially offer an electrolyte-free detection platform for sensitive and rapid biosensors.