Polymer Institute, Slovak Academy of Sciences, Dúbravská cesta 9, 845 41 Bratislava, Slovakia.
J Chem Phys. 2017 Oct 7;147(13):134907. doi: 10.1063/1.4991649.
Equilibrium conformation of a semiflexible macromolecule in an array of nanoposts exhibits a non-monotonic behavior both at variation of the chain stiffness and increased crowding imposed by nanoposts. This is a result of the competition between the axial chain extension in channel-like interstitial volumes between nanoposts and the chain partitioning among these volumes. The approximation of a nanopost array as a combination of a quasi-channel and a quasi-slit like geometry semi-qualitatively explains the behavior of a chain in the array. In this approximation, the interstitial spaces are viewed as being of the channel geometry, while the passages between two adjacent posts are viewed as being of the slit geometry. Interestingly, the stiffer chains tend to penetrate more readily through the passage apertures, in the direction perpendicular to the post axes, and thus to occupy more interstitial volumes. This is consistent with the prediction of the free-energy penalty that is lower for a stiffer chain at strong slit-like confinement. These findings can find applications in the control of macromolecular conformations in recent nanotechnological techniques with bio-macromolecules such as a DNA.
在纳米柱阵列中，半柔性大分子的平衡构象在链刚性变化和纳米柱增加引起的拥挤程度增加的情况下表现出非单调行为。这是由于轴向链在纳米柱之间的通道状间隙体积中的延伸与这些体积之间的链分区之间的竞争所致。将纳米柱阵列近似为准通道和准狭缝几何形状的组合，可以半定量地解释链在阵列中的行为。在该近似中，将间隙空间视为具有通道几何形状，而两个相邻柱之间的通道则视为具有狭缝几何形状。有趣的是，刚性链更倾向于垂直于柱轴的方向更容易地穿透通道开口，并因此占据更多的间隙体积。这与自由能惩罚的预测一致，即对于强狭缝状限制下的刚性链，自由能惩罚更低。这些发现可应用于最近的纳米技术技术中生物大分子（如 DNA）的控制大分子构象。
