Coil−Stretch Transition of DNA Molecules in Slitlike Confinement
Author(s)Tang, Jing; Trahan, Daniel W.; Doyle, Patrick S.
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We experimentally investigate the influence of slitlike confinement on the coil−stretch transition of single DNA molecules in a homogeneous planar elongational electric field. We observe a more gradual coil−stretch transition characterized by two distinct critical strain rates for DNA in confinement, different from the unconfined case where a single critical strain rate exists. We postulate that the change in the coil−stretch transition is due to a modified spring law in confinement. We develop a dumbbell model to extract an effective spring law by following the relaxation of an initially stretched DNA. We then use this spring law and kinetic theory modeling to predict the extension and fluctuations of DNA in planar elongational fields. The model predicts that a two-stage coil−stretch transition emerges in confinement, in accord with experimental observations.
DepartmentMassachusetts Institute of Technology. Department of Chemical Engineering
American Chemical Society
Tang, Jing, Daniel W. Trahan, and Patrick S. Doyle. Coil−Stretch Transition of DNA Molecules in Slitlike Confinement. Macromolecules 43, no. 6 (March 23, 2010): 3081-3089.
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