Single-Molecule Detection of DNA in a Nanochannel by High-Field Strength-Assisted Electrical Impedance Spectroscopy
Single-Molecule Detection of DNA in a Nanochannel by High-Field Strength-Assisted Electrical Impedance Spectroscopy
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DOI：
10.3390/mi10030189
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发表时间：
2019-03
期刊：
影响因子：
3.4
通讯作者：
P. Pungetmongkol;Takatoki Yamamoto
中科院分区：
文献类型：
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作者：
P. Pungetmongkol;Takatoki Yamamoto
许多研究人员已经制造了微和纳流控器件，结合光学，化学和电学检测系统，目的是实现大分子的芯片分析。本研究证明了一种无标记的DNA检测使用的纳米流体装置的基础上，阻抗测量，既灵敏又操作简单。利用该装置研究了电泳和介电泳对DNA构象的影响以及长度依赖性。向纳米间隙电极施加低交流电压以在非法拉第条件下产生高强度场（> 0.5MV/m）。此外，将100 nm厚的金电极完全嵌入基底中，以允许直接测量通过差距的含有样品的溶液，而不需要任何表面改性。该装置中的高强度场产生介电泳力，该介电泳力基于电极之间的来回运动以特定频率将DNA分子拉伸穿过电极间隙，其中DNA处于无规卷曲构象。对100 bp、500 bp、1 kbp、5 kbp、10 kbp和48 kbp λ DNA的构象特征进行了高分辨率定量分析。发现该系统的灵敏度比从用于分析生物聚合物的常规线性交流（AC）阻抗获得的灵敏度高出约10个数量级。这种新的高灵敏度的过程，预计将有利于复杂的大分子和纳米粒子的研究。
Many researchers have fabricated micro and nanofluidic devices incorporating optical, chemical, and electrical detection systems with the aim of achieving on-chip analysis of macromolecules. The present study demonstrates a label-free detection of DNA using a nanofluidic device based on impedance measurements that is both sensitive and simple to operate. Using this device, the electrophoresis and dielectrophoresis effect on DNA conformation and the length dependence were examined. A low alternating voltage was applied to the nanogap electrodes to generate a high intensity field (>0.5 MV/m) under non-faradaic conditions. In addition, a 100 nm thick gold electrode was completely embedded in the substrate to allow direct measurements of a solution containing the sample passing through the gap, without any surface modification required. The high intensity field in this device produced a dielectrophoretic force that stretched the DNA molecule across the electrode gap at a specific frequency, based on back and forth movements between the electrodes with the DNA in a random coil conformation. The characteristics of 100 bp, 500 bp, 1 kbp, 5 kbp, 10 kbp, and 48 kbp λ DNA associated with various conformations were quantitatively analyzed with high resolution (on the femtomolar level). The sensitivity of this system was found to be more than about 10 orders of magnitude higher than that obtained from conventional linear alternating current (AC) impedance for the analysis of bio-polymers. This new high-sensitivity process is expected to be advantageous with regard to the study of complex macromolecules and nanoparticles.