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Diffusion and flow in complex liquids.

Karol Makuch1, Robert Hołyst2, Tomasz Kalwarczyk2

  • 1Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland. kmakuch@ichf.edu.pl rholyst@ichf.edu.pl and Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.

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Summary
This summary is machine-generated.

This study introduces a new theory for diffusion in complex liquids, crucial for understanding cellular processes. It enables accurate prediction of diffusion rates and reduces computational costs for nanoscale transport simulations.

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Area of Science:

  • Physics
  • Biophysics
  • Physical Chemistry

Background:

  • Diffusion in liquids is fundamental to chemical and biological processes.
  • The Stokes-Einstein relation accurately describes diffusion in simple liquids but fails in complex biological media.
  • Accurate modeling of nanoscale transport in living cells requires a theoretical framework for viscous response.

Purpose of the Study:

  • To develop a theoretical framework for describing viscous response and diffusion in complex fluids.
  • To enable predictions of diffusion rates in complex media, particularly within biological systems.
  • To provide a method for determining wave-vector-dependent viscosity directly from experimental data.

Main Methods:

  • Utilized a general framework describing viscosity as a function of the wave vector, η(k).
  • Developed a formulation to relate rotational and translational diffusion coefficients.
  • Applied the theory to create databases for protein diffusion in E. coli and protein-DNA interactions.

Main Results:

  • Established a method to determine wave-vector-dependent viscosity η(k) experimentally.
  • Generated databases for rotational diffusion coefficients of proteins in E. coli.
  • Provided diffusion coefficients for proteins interacting with DNA, enabling prediction of association rate constants.

Conclusions:

  • The proposed theoretical framework accurately describes diffusion and viscosity in complex fluids.
  • The formulation offers a significant reduction in computational cost for simulating transport in crowded environments.
  • This work provides essential parameters for predicting molecular interactions and transport within biological cells.