Nonmonotonic diffusion of particles among larger attractive crowding spheres

We study the diffusive motion of particles among fixed spherical crowders. The diffusers interact with the crowders through a combination of a hard-core repulsion and a short-range attraction. The long-time effective diffusion coefficient of the diffusers is found to depend nonmonotonically on the s...

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Bibliographic Details
Published inPhysical review letters Vol. 113; no. 13; p. 138302
Main Authors Putzel, Gregory Garbès, Tagliazucchi, Mario, Szleifer, Igal
Format Journal Article
LanguageEnglish
Published United States 26.09.2014
Subjects
Crowding
Diffusion
DNA - chemistry
DNA - metabolism
Models, Chemical
Molecular Dynamics Simulation
Proteins - chemistry
Proteins - metabolism
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Summary:We study the diffusive motion of particles among fixed spherical crowders. The diffusers interact with the crowders through a combination of a hard-core repulsion and a short-range attraction. The long-time effective diffusion coefficient of the diffusers is found to depend nonmonotonically on the strength of their attraction to the crowders. That is, for a given concentration of crowders, a weak attraction to the crowders enhances diffusion. We show that this counterintuitive fact can be understood in terms of the mesoscopic excess chemical potential landscape experienced by the diffuser. The roughness of this excess chemical potential landscape quantitatively captures the nonmonotonic dependence of the diffusion rate on the strength of crowder-diffuser attraction; thus, it is a purely static predictor of dynamic behavior. The mesoscopic view given here provides a unified explanation for enhanced diffusion effects that have been found in various systems of technological and biological interest.
ISSN:1079-7114
DOI:10.1103/PhysRevLett.113.138302