Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA.
Nat Nanotechnol. 2010 Feb;5(2):160-5. doi: 10.1038/nnano.2009.379. Epub 2009 Dec 20.
Solid-state nanopores are sensors capable of analysing individual unlabelled DNA molecules in solution. Although the critical information obtained from nanopores (for example, DNA sequence) comes from the signal collected during DNA translocation, the throughput of the method is determined by the rate at which molecules arrive and thread into the pores. Here, we study the process of DNA capture into nanofabricated SiN pores of molecular dimensions. For fixed analyte concentrations we find an increase in capture rate as the DNA length increases from 800 to 8,000 base pairs, a length-independent capture rate for longer molecules, and increasing capture rates when ionic gradients are established across the pore. Furthermore, we show that application of a 20-fold salt gradient allows the detection of picomolar DNA concentrations at high throughput. The salt gradients enhance the electric field, focusing more molecules into the pore, thereby advancing the possibility of analysing unamplified DNA samples using nanopores.
固态纳米孔是一种能够分析溶液中单个未标记 DNA 分子的传感器。尽管纳米孔获取的关键信息（例如 DNA 序列）来自于 DNA 转导过程中收集的信号，但该方法的通量取决于分子进入和穿过孔的速度。在这里，我们研究了 DNA 捕获到分子尺寸的纳米制造 SiN 孔中的过程。对于固定的分析物浓度，我们发现随着 DNA 长度从 800 到 8000 个碱基对的增加，捕获率会增加，对于较长的分子，捕获率是独立的，并且当在孔中建立离子梯度时，捕获率会增加。此外，我们表明，应用 20 倍盐梯度可以在高通量下检测到皮摩尔级的 DNA 浓度。盐梯度增强了电场，将更多的分子聚焦到孔中，从而提高了使用纳米孔分析未经扩增的 DNA 样本的可能性。
