Berlin 2015 – scientific programme

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BP: Fachverband Biologische Physik

BP 34: Statistical Physics of Biological Systems II (joint BP/DY/CPP)

BP 34.5: Talk

Wednesday, March 18, 2015, 10:30–10:45, H 1028

Scaling Regimes for Confined Wormlike Chains under Tension — •Greg Morrison¹ and Dave Thirumalai² — ¹IMT Lucca Institute for Advanced Studies, Lucca Italy 55100 — ²University of Maryland at College Park, College Park MD 20742

In this talk, we study the scaling behavior of a wormlike chain (WLC) with persistence length l_p confined to the surface of a cylinder of radius R under the application of an external tension. Inextensibility and confinement effects are treated on a mean field level, and we show that the stationary solution for the mean field parameters can be reduced simple equations that can be solved asymptotically. We are able to accurately recover the well known Odijk scaling of F∼ L/l_d, with the deflection length l_d=(l_pR²)^1/3, for strongly confined chains and show that this scaling is robust to weak external forces. We show that the scaling regimes for both weakly and strongly confined polymers change drastically under application of large external tension, with F∼ L/l_t for a tensile length scale l_t∼ (l_p/β f)^1/2. Our results may be relevant in the mechanical unbinding of histone-bound DNA as well as a variety of experimental situations involving DNA confined to nanochannels.