Department of Physical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, S. A. S. Nagar, Mohali, 140306, Punjab, India.
Sci Rep. 2022 Nov 9;12(1):19081. doi: 10.1038/s41598-022-21845-6.
We study the translocation of a semiflexible polymer through a conical channel with attractive surface interactions and a driving force which varies spatially inside the channel. Using the results of the translocation dynamics of a flexible polymer through an extended channel as control, we first show that the asymmetric shape of the channel gives rise to non-monotonic features in the total translocation time as a function of the apex angle of the channel. The waiting time distributions of individual monomer beads inside the channel show unique features strongly dependent on the driving force and the surface interactions. Polymer stiffness results in longer translocation times for all angles of the channel. Further, non-monotonic features in the translocation time as a function of the channel angle changes substantially as the polymer becomes stiffer, which is reflected in the changing features of the waiting time distributions. We construct a free energy description of the system incorporating entropic and energetic contributions in the low force regime to explain the simulation results.
我们研究了带有吸引力表面相互作用的锥形通道中半柔性聚合物的输运,以及通道内空间变化的驱动力。利用柔性聚合物通过扩展通道的输运动力学结果作为对照,我们首先表明,通道的不对称形状导致总输运时间作为通道顶点角度的函数出现非单调特征。通道内单个单体珠的等待时间分布显示出强烈依赖于驱动力和表面相互作用的独特特征。对于所有角度的通道,聚合物的刚性都会导致更长的输运时间。此外,随着聚合物变得越来越硬,作为函数的输运时间的非单调特征在通道角度上的变化也发生了很大的变化,这反映在等待时间分布的变化特征上。我们构建了一个系统的自由能描述,在低力区域包含了熵和能量贡献,以解释模拟结果。