Institute for Nano- and Microfluidics, Technische Universität Darmstadt, Darmstadt, Germany.
Soft Matter. 2017 Sep 20;13(36):6189-6196. doi: 10.1039/c7sm00306d.
We study the effect of pressure-driven flow on a single surface-tethered DNA molecule confined between parallel surfaces. The influence of flow and channel parameters as well as the length of the molecules on their extension and orientation is explored. In the experiments the chain conformations are imaged by laser scanning confocal microscopy. We find that the fractional extension of the tethered DNA molecules mainly depends on the wall shear stress, with effects of confinement being very weak. Experiments performed with molecules of different contour length show that the fractional extension is a universal function of the product of the wall shear stress and the contour length, a result that can be obtained from a simple scaling relation. The experimental results are in good agreement with results from coarse-grained molecular dynamics/Lattice-Boltzmann simulations.
我们研究了压力驱动流动对平行表面之间受限的单个表面束缚 DNA 分子的影响。探讨了流动和通道参数以及分子长度对其延伸和取向的影响。在实验中，通过激光扫描共焦显微镜对链构象进行成像。我们发现，束缚 DNA 分子的分数延伸主要取决于壁面剪切应力，而约束的影响非常弱。用不同轮廓长度的分子进行的实验表明，分数延伸是壁面剪切应力和轮廓长度乘积的通用函数，这一结果可以从一个简单的标度关系得到。实验结果与粗粒化分子动力学/格子玻尔兹曼模拟的结果非常吻合。
