Tethered DNA dynamics in shear flow.

Stretching tethered DNA chains in shear flow

– We discuss the stretching of tethered chains subject to a shear flow. Fluorescence microscopy measurements of the extension of sheared tethered DNA, “model polymers”, of various lengths are presented. The tethered chains approach full extension as the flow rate is increased, but very slowly. We show that a general theory to understand the large deformation of any sheared tethered chain must i...

Dynamics of a tethered polymer in shear flow.

The dynamics of a single polymer tethered to a solid surface in a shear flow was observed using fluorescently labeled DNA chains. Dramatic shear enhanced temporal fluctuations in the chain extension were observed. The rate of these fluctuations initially decreased for increasing shear rate gamma; and increased above a critical gamma;. Simulations revealed that these anomalous dynamics arise fro...

Cyclic motion of a grafted polymer under shear flow.

The long-time dynamics of a single end-tethered chain under shear flow are studied using molecular and Brownian dynamics simulations of a flexible polymer. As observed in previous experiments with tethered DNA [Phys. Rev. Lett. 84, 4769 (2000)], under a flow sheared at constant rate the chain performs a cyclic motion. But, contrary to what has been previously suggested, a well-defined character...

Supporting Information for: The role of near-wall drag effect on the dynamics of tethered DNA under shear flow

Direct imaging of single-molecules: from dynamics of a single DNA chain to the study of complex DNA-protein interactions.

Recent years have seen significant advances in the characterization and manipulation of individual molecules. The combination of single-molecule fluorescence and micromanipulation enables one to study physical and biological systems at new length scales, to unravel qualitative mechanisms, and to measure kinetic parameters that cannot be addressed by traditional biochemistry. DNA is one of the m...