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Diffusion-Limited Reactions in Crowded Environments

N. Dorsaz, C. De Michele, F. Piazza, P. De Los Rios, and G. Foffi
Phys. Rev. Lett. 105, 120601 – Published 13 September 2010
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Abstract

Diffusion-limited reactions are usually described within the Smoluchowski theory, which neglects interparticle interactions. We propose a simple way to incorporate excluded-volume effects building on simulations of hard sphere in the presence of a sink. For large values of the sink-to-particle size ratio Rs, the measured encounter rate is in good agreement with a simple generalization of the Smoluchowski equation at high densities. Reducing Rs, the encounter rate is substantially depressed and becomes even nonmonotonic for Rs1. Concurrently with the saturation of the rate, stationary density waves set in close to the sink. A mean-field analysis helps to shed light on the subtle link between such ordering and the slowing down of the encounter dynamics. Finally, we show how an infinitesimal amount of nonreacting impurities can equally slow down dramatically the reaction.

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  • Received 14 June 2010

DOI:https://doi.org/10.1103/PhysRevLett.105.120601

© 2010 The American Physical Society

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Speeding up in a crowd

Published 13 September 2010

New simulations show that a high concentration of molecules can significantly increase the rate of reaction between two molecules, but does the setup reflect realities of biochemical reactions inside cells?

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Authors & Affiliations

N. Dorsaz1, C. De Michele2, F. Piazza3,*, P. De Los Rios3, and G. Foffi4

  • 1University of Fribourg, Adolphe Merkle Institute, CH-1723 Marly 1, Switzerland
  • 2Universita di Roma La Sapienza, Dipartimento di Fisica, P.le Aldo Moro 2, 00185 Roma, Italy
  • 3Ecole Polytechnique Fédérale de Lausanne (EPFL), Institute of Theoretical Physics, Laboratory of Statistical Biophysics, 1015 Lausanne, Switzerland
  • 4Ecole Polytechnique Fédérale de Lausanne (EPFL), Institute of Theoretical Physics, 1015 Lausanne, Switzerland

  • *Present address: Centre de Biophysique Moléculaire (CBM-CNRS), Rue Charles Sadron, 45071 Cedex 2 Orléans, France.

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Issue

Vol. 105, Iss. 12 — 17 September 2010

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