Extension of nanoconfined DNA: Quantitative comparison between experiment and theory
Extension of nanoconfined DNA: Quantitative comparison between experiment and theory
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DOI：
10.1103/physreve.92.062701
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发表时间：
2015-12-02
影响因子：
2.4
通讯作者：
Mehlig, B.
中科院分区：
文献类型：
--
作者：
Iarko, V.;Werner, E.;Mehlig, B.
限制在纳米通道中的DNA的延伸已经被深入和详细地研究。然而，实验和模型计算之间的定量比较是困难的，因为大多数理论预测涉及不确定的前因子，因为模型参数（轮廓长度，库恩长度，有效宽度）是难以可靠地计算，导致大量的不确定性。在这里，我们使用最近的渐近精确理论的DNA延伸的“扩展德Gennes政权”，使我们能够比较实验结果与理论。为了这个目的，我们进行了实验，测量平均DNA延伸和它的标准偏差，同时改变通道的几何形状，染料嵌入比，和缓冲液的离子强度。在高离子强度下，实验结果与理论值吻合得很好，表明模型参数是可靠的。在低离子强度下，一致性不太好。我们讨论可能的原因。原则上，我们的方法允许我们测量单个DNA分子的库恩长度和有效宽度，并且更一般地测量溶液中的半柔性聚合物的库恩长度和有效宽度。
The extension of DNA confined to nanochannels has been studied intensively and in detail. However, quantitative comparisons between experiments and model calculations are difficult because most theoretical predictions involve undetermined prefactors, and because the model parameters (contour length, Kuhn length, effective width) are difficult to compute reliably, leading to substantial uncertainties. Here we use a recent asymptotically exact theory for the DNA extension in the "extended de Gennes regime" that allows us to compare experimental results with theory. For this purpose, we performed experiments measuring the mean DNA extension and its standard deviation while varying the channel geometry, dye intercalation ratio, and ionic strength of the buffer. The experimental results agree very well with theory at high ionic strengths, indicating that the model parameters are reliable. At low ionic strengths, the agreement is less good. We discuss possible reasons. In principle, our approach allows us to measure the Kuhn length and the effective width of a single DNA molecule and more generally of semiflexible polymers in solution.