Surface-induced effects in fluctuation-based measurements of single-polymer elasticity: A direct probe of the radius of gyration
Surface-induced effects in fluctuation-based measurements of single-polymer elasticity: A direct probe of the radius of gyration
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DOI：
10.1063/1.5009049
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发表时间：
2018-03-28
影响因子：
4.4
通讯作者：
Saleh, Omar A.
中科院分区：
文献类型：
--
作者：
Innes-Gold, Sarah N.;Morgan, Ian L.;Saleh, Omar A.
聚合物弹性的单分子测量是对生物分子结构和聚合物物理原理的强大、直接的探测。最近的工作揭示了通过基于斑点的比例模型来理解生物聚合物弹性的低力机制。然而，观察这些体系所需的微小张力有可能造成测量偏差，特别是由于聚合物链与系留表面的相互作用增加。在这里，我们检查了一个实验观察到的偏差，其中基于波动的弹性估计报告了出人意料的低链顺应性。结果表明，通过对聚合物构型的镜像方法计算，该效应与基于量化表面排斥效应的预测是一致的。分析表明，该效应发生在与聚合物的零张力回转半径成反比的外张力下。我们利用这一点来证明一个自洽的方案来估计系留聚合物的旋转半径。这体现在对透明质酸和聚乙二醇链的测量上。由AIP出版公司出版。
Single-molecule measurements of polymer elasticity are powerful, direct probes of both biomolecular structure and principles of polymer physics. Recent work has revealed low-force regimes in which biopolymer elasticity is understood through blob-based scaling models. However, the small tensions required to observe these regimes have the potential to create measurement biases, particularly due to the increased interactions of the polymer chain with tethering surfaces. Here, we examine one experimentally observed bias, in which fluctuation-based estimates of elasticity report an unexpectedly low chain compliance. We show that the effect is in good agreement with predictions based on quantifying the exclusion effect of the surface through an image-method calculation of available polymer configurations. The analysis indicates that the effect occurs at an external tension inversely proportional to the polymer's zero-tension radius of gyration. We exploit this to demonstrate a self-consistent scheme for estimating the radius of gyration of the tethered polymer. This is shown in measurements of both hyaluronic acid and poly(ethylene glycol) chains. Published by AIP Publishing.