Label-Free Detection of Few Copies of DNA with Carbon Nanotube Impedance Biosensors
Label-Free Detection of Few Copies of DNA with Carbon Nanotube Impedance Biosensors
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DOI：
10.1002/anie.201006806
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发表时间：
2011-01-01
影响因子：
16.6
通讯作者：
Balasubramanian, Kannan
中科院分区：
文献类型：
--
作者：
Kurkina, Tetiana;Vlandas, Alexis;Balasubramanian, Kannan
特定核酸序列的检测在环境、食品、临床监测以及法医筛查中发挥着至关重要的作用。 [1]检测少量 DNA 拷贝的能力预计将对各种疾病的快速现场检测产生广泛影响。 [2]在当前方法中，通过使用聚合酶链式反应 (PCR) 扩增样品可以获得可检测量的 DNA。 [3]对于涉及比较基因表达水平的应用，使用微阵列。[4]这种方法需要标记目标序列，以便随后用荧光显微镜进行检测。对 PCR、标记和笨重的光学读取仪器的需求限制了此类传感器在护理点应用中的使用。可以避免 PCR 或标记步骤的新方法将是有利的；此外，还需要一种便携式、经济高效的传感设备。电气方法非常适合此目的，因为它们不需要对目标进行标记，并且与紧凑和便携式格式兼容。 DNA 的无标记电检测已在许多配置中得到证实，[5] 其中大多数基于场效应 [6, 7] 或电化学检测。 [8]尽管在这些实验中避免使用标记，但检测限与光学方法相当。因此，还需要扩增步骤。为了提高检测限，纳米结构已被提议作为生物传感器有源元件的合适替代品。[9-11]一维纳米结构是有前途的候选者，因为它们可以轻松地用作场效应晶体管的有源元件。[7, 11-13]此外，一维纳米结构，例如单壁碳纳米管（CNT），其表面上有所有原子。由于每个原子都会限制流过它的电流，因此这些结构有望实现绝对灵敏度。
The detection of specific nucleic acid sequences plays a vital role in environmental, food, and clinical monitoring and in forensic screening.[1] The ability to detect few copies of DNA is expected to have a broad impact on the rapid on-site detection of various diseases.[2] In current methods, amplification of the sample through the use of the polymerase chain reaction (PCR) enables a detectable amount of DNA to be obtained.[3] For applications involving the comparison of gene expression levels, microarrays are used.[4] This approach requires the labeling of target sequences for subsequent detection with a fluorescence microscope. The need for PCR, labeling, and a bulky optical reading instrument limits the use of such sensors for point-of-care applications. New methods in which PCR or labeling steps could be avoided would be advantageous; furthermore, a portable, cost-effective sensing device is required.Electrical methods are ideally suited for this purpose, since they do not require the target to be labeled and are compatible with a compact and portable format. Label-free electrical detection of DNA has been demonstrated in many configurations,[5] the majority of which are based on fieldeffect [6, 7] or electrochemical detection.[8] Although the use of a label is avoided in these experiments, the limit of detection is comparable to that of optical methods; hence, an amplification step is also required. To improve the limit of detection, nanostructures have been proposed as suitable alternatives for active elements of biosensors.[9–11] One-dimensional nanostructures are promising candidates, since they can be used as active elements of field-effect transistors in a facile manner.[7, 11–13] Furthermore, a 1D nanostructure, such as a single-walled carbon nanotube (CNT), has all atoms on its surface. Since every atom limits the current flowing through it, these structures show promise for absolute sensitivity.