Conformational analysis of single DNA molecules undergoing entropically induced motion in nanochannels
Conformational analysis of single DNA molecules undergoing entropically induced motion in nanochannels
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DOI：
10.1529/biophysj.105.074732
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发表时间：
2006-06-01
影响因子：
3.4
通讯作者：
Craighead, H. G.
中科院分区：
文献类型：
--
作者：
Mannion, J. T.;Reccius, C. H.;Craighead, H. G.
我们已经使用纳米通道和微通道之间的界面作为在DNA分子上施加受控力的工具。跨越这种界面的回转半径大于纳米通道宽度的分子受到基本上恒定的熵力，该熵力可以与其他力平衡，例如来自施加的电场的电泳力。通过控制施加的场，我们可以根据需要定位分子，并观察分子从纳米通道拉伸、松弛和反冲时的构象。我们量化和目前的分子运动的模型，在响应熵，电泳，和摩擦力作用于它。通过确定的大小的DNA分子在纳米结构中的阻力系数，我们能够估计的约束引起的反冲力。最后，我们证明，我们可以使用一个受控的外加场和熵的界面力展开分子，然后可以操纵和定位在其简单的扩展形态。
We have used the interface between a nanochannel and a microchannel as a tool for applying controlled forces on a DNA molecule. A molecule, with a radius of gyration larger than the nanochannel width, that straddles such an interface is subject to an essentially constant entropic force, which can be balanced against other forces such as the electrophoretic force from an applied electric field. By controlling the applied field we can position the molecule as desired and observe the conformation of the molecule as it stretches, relaxes, and recoils from the nanochannel. We quantify and present models for the molecular motion in response to the entropic, electrophoretic, and frictional forces acting on it. By determining the magnitude of the drag coefficients for DNA molecules in the nanostructure, we are able to estimate the confinement-induced recoil force. Finally, we demonstrate that we can use a controlled applied field and the entropic interfacial forces to unfold molecules, which can then be manipulated and positioned in their simple extended morphology.