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Diffusion of Short Semiflexible DNA Polymer Chains in Strong and Moderate Confinement
ACS Macro Letters ( IF 5.1 ) Pub Date : 2021-09-17 , DOI: 10.1021/acsmacrolett.1c00470
Gregory T Morrin 1 , Daniel F Kienle 1 , Daniel K Schwartz 1
Affiliation  

In many technological applications, DNA is confined within nanoenvironments that are smaller than the size of the unconfined polymer in solution. However, the dependence of the diffusion coefficient on molecular weight and characteristic confinement dimension remains poorly understood in this regime. Here, convex lens-induced confinement (CLiC) was leveraged to examine how the diffusion of short DNA fragments varied as a function of slit height by using single-molecule fluorescence tracking microscopy. The diffusion coefficient followed approximate power law behavior versus confinement height, with exponents of 0.27 ± 0.01, 0.32 ± 0.02, and 0.42 ± 0.06 for 692, 1343, and 2686 base pair chains, respectively. The weak dependence on slit height suggests that shorter semiflexible chains may adopt increasingly rodlike conformations and therefore experience weaker excluded-volume interactions as the confinement dimension is reduced. The diffusion coefficient versus molecular weight also exhibited apparent power law behavior, with exponents that varied slightly (from −0.89 to −0.85) with slit height, consistent with hydrodynamic interactions intermediate between Rouse and Zimm model predictions.

中文翻译:

短半柔性 DNA 聚合物链在强和中等限制条件下的扩散

在许多技术应用中,DNA 被限制在比溶液中不受限制的聚合物尺寸更小的纳米环境中。然而,在这种情况下,扩散系数对分子量和特征限制尺寸的依赖性仍然知之甚少。在这里,利用凸透镜诱导的限制 (CLiC) 通过使用单分子荧光跟踪显微镜检查短 DNA 片段的扩散如何随狭缝高度的变化而变化。扩散系数遵循近似幂律行为与限制高度的关系,对于 692、1343 和 2686 个碱基对链,指数分别为 0.27 ± 0.01、0.32 ± 0.02 和 0.42 ± 0.06。对狭缝高度的弱依赖性表明,较短的半柔性链可能会采用越来越多的棒状构象,因此随着限制尺寸的减小,排除体积相互作用会减弱。扩散系数与分子量的关系也表现出明显的幂律行为,指数随狭缝高度略有变化(从-0.89 到-0.85),这与 Rouse 和 Zimm 模型预测之间的中间流体动力学相互作用一致。
更新日期:2021-10-19
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