DNA Interactions in Crowded Nanopores
DNA Interactions in Crowded Nanopores
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DOI：
10.1021/nl401050m
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发表时间：
2013-06-01
期刊：
影响因子：
10.8
通讯作者：
Keyser, Ulrich F.
中科院分区：
文献类型：
--
作者：
Laohakunakorn, Nadanai;Ghosal, Sandip;Keyser, Ulrich F.
DNA 在拥挤环境中的运动是物理学和生物学的一个共同主题。例子包括凝胶电泳以及细胞和病毒衣壳内 DNA 的自相互作用。在这里，我们通过将 DNA 束缚在激光光阱中的珠子上以产生“分子拔河”来研究纳米孔内多个 DNA 分子的相互作用。我们测量了该系绳力与孔中 DNA 分子数量的函数关系，结果表明每个分子的力随着分子数量的增加而减小。基于多个 DNA 链之间流体动力学相互作用的平均场理论的简单缩放论证解释了我们的观察结果。在高盐浓度下，当德拜长度接近反离子的大小时，每个分子的力基本上与分子的数量无关。我们将此归因于电渗流的急剧减少，这使得流体动力相互作用无效。
The motion of DNA in crowded environments is a common theme in physics and biology. Examples include gel electrophoresis and the self-interaction of DNA within cells and viral capsids. Here we study the interaction of multiple DNA molecules within a nanopore by tethering the DNA to a bead held in a laser optical trap to produce a "molecular tug-of-war". We measure this tether force as a function of the number of DNA molecules in the pore and show that the force per molecule decreases with the number of molecules. A simple scaling argument based on a mean field theory of the hydrodynamic interactions between multiple DNA strands explains our observations. At high salt concentrations, when the Debye length approaches the size of the counterions, the force per molecule becomes essentially independent of the number of molecules. We attribute this to a sharp decrease in electroosmotic flow which makes the hydrodynamic interactions ineffective.