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Single-Polymer Friction Force Microscopy of dsDNA Interacting with a Nanoporous Membrane
Kordula Schellnhuber1,2, Johanna Blass1, Hanna Hübner3
1INM─Leibniz Institute for New Materials, 66123 Saarbrücken, Germany.
Langmuir : the ACS Journal of Surfaces and Colloids
|December 20, 2023
Summary
Friction arises from polymer entanglements. Researchers studied DNA polymer forces interacting with nanopores, revealing how polymer stretching and detachment influence friction at different speeds.
Area of Science:
- Polymer Science
- Tribology
- Biophysics
Background:
- Surface-grafted polymers reduce friction via osmotic pressure.
- However, polymer entanglement can increase friction during sliding.
- Understanding these dual roles is crucial for designing low-friction surfaces.
Purpose of the Study:
- To investigate the forces acting on a single DNA polymer interacting with nanopores.
- To analyze the relationship between polymer dynamics, pore interactions, and friction.
- To elucidate the mechanisms of friction contribution from fluctuating polymers.
Main Methods:
- Utilized atomic force microscopy (AFM) to probe a single double-stranded DNA polymer.
- Studied interactions between the DNA polymer and nanometer-scale methylated pores in a polystyrene-block-poly(4-vinylpyridine) membrane.
- Measured forces, detachment events, and attachment frequency at varying velocities.
Main Results:
- Observed rare binding events of the DNA polymer into the nanopores.
- Characterized polymer stretching between the AFM tip and the membrane surface prior to detachment.
- Quantified the velocity dependence of detachment forces and attachment frequency.
Conclusions:
- Polymer stretching and force-induced detachment are key mechanisms in friction.
- Friction is influenced by the polymer's rare excursions beyond its equilibrium state.
- These findings provide insights into polymer-surface interactions and friction control.
