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Stretching of surface-tethered polymers in pressure-driven flow under confinement
Tamal Roy1, Kai Szuttor, Jens Smiatek
1Institute for Nano- and Microfluidics, Technische Universität Darmstadt, Darmstadt, Germany. hardt@nmf.tu-darmstadt.de.
Soft Matter
|August 12, 2017
Summary
We investigated how fluid flow affects tethered DNA molecules. DNA extension primarily depends on wall shear stress, not confinement, and scales universally with shear stress and molecule length.
Area of Science:
- Biophysics
- Fluid Dynamics
- Polymer Physics
Background:
- Understanding DNA behavior under flow is crucial for molecular biology and nanotechnology.
- Confined geometries influence polymer dynamics, but their specific impact on tethered DNA under flow requires detailed study.
Purpose of the Study:
- To investigate the effect of pressure-driven flow on single surface-tethered DNA molecules confined between parallel surfaces.
- To determine how flow, channel parameters, and DNA length influence molecular extension and orientation.
Main Methods:
- Experiments using laser scanning confocal microscopy to image DNA chain conformations.
- Utilizing coarse-grained molecular dynamics/Lattice-Boltzmann simulations for comparison.
Main Results:
- Fractional extension of tethered DNA molecules is predominantly governed by wall shear stress.
- Confinement effects on DNA extension were found to be minimal.
- DNA extension exhibits a universal dependence on the product of wall shear stress and contour length.
Conclusions:
- Wall shear stress is the primary factor dictating the extension of flow-tethered DNA.
- A universal scaling law describes DNA extension, simplifying predictions in confined flow systems.
- Experimental findings align well with simulation results, validating the models used.
