Global cross-over dynamics of single semiflexible polymers

TL;DR

This paper develops a comprehensive mean-field dynamical theory for single semiflexible polymers, accurately describing their kinetics across various length and time scales, including complex cross-over behaviors, validated by experiments and simulations.

Contribution

The paper introduces a parameter-free, global theory that captures cross-over dynamics of semiflexible polymers, integrating hydrodynamic interactions and validated against experiments and simulations.

Findings

Accurately models DNA monomer kinetics over three decades of length and five decades of time.

Successfully captures cross-over behaviors between stiffness-dominated and flexible regimes.

Validated by fluorescence correlation spectroscopy and Brownian hydrodynamics simulations.

Abstract

We present a mean-field dynamical theory for single semiflexible polymers which can precisely capture, without fitting parameters, recent fluorescence correlation spectroscopy results on single monomer kinetics of DNA strands in solution. Our approach works globally, covering three decades of strand length and five decades of time: it includes the complex cross-overs occurring between stiffness-dominated and flexible bending modes, along with larger-scale rotational and center-of-mass motion. The accuracy of the theory stems in part from long-range hydrodynamic coupling between the monomers, which makes a mean-field description more realistic. Its validity extends even to short, stiff fragments, where we also test the theory through Brownian hydrodynamics simulations.