Measuring the Confinement Free Energy and Effective Width of Single Polymer Chains via Single-Molecule Tetris

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• 作者：Alexander R. Klotz ; Lyndon Duong ; Mikhail Mamaev ; Hendrick W. de Haan ; Jeff Z. Y. Chen ; Walter W. Reisner
• 刊名：Macromolecules
• 出版年：2015
• 出版时间：July 28, 2015
• 年：2015
• 卷：48
• 期：14
• 页码：5028-5033
• 全文大小：388K
• ISSN：1520-5835

文摘

We perform single-molecule partitioning measurements of the free energy of chain confinement and self-exclusion as a function of confinement dimension and buffer ionic strength via single-molecule Tetris. Individual DNA chains, confined in a nanoslit with a lattice of embedded nanocavities, partition their contour between the cavities. Changes in device geometry and buffer chemistry lead to changes in the number of cavities occupied. We are able to deduce the confinement free energy difference between the nanocavities and the nanoslit by observing how the number of cavities occupied by a single chain varies as a function of device dimension. These measurements enable us to confirm theoretical predictions for confinement free energy based on worm-like chain formalism and quantify the chain effective width w, providing a direct measure of the size of excluded-volume effect on a single-chain level.