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Diffusioosmotic and convective flows induced by a nonelectrolyte concentration gradient

Glucose is an important energy source in our bodies, and its consumption results in gradients over length scales ranging from the subcellular to entire organs. Concentration gradients can drive material transport through both diffusioosmosis and convection. Convection arises because concentration gr...

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Autores principales: Williams, Ian, Lee, Sangyoon, Apriceno, Azzurra, Sear, Richard P., Battaglia, Giuseppe
Formato: Online Artículo Texto
Lenguaje:English
Publicado: National Academy of Sciences 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7568292/
https://www.ncbi.nlm.nih.gov/pubmed/32989158
http://dx.doi.org/10.1073/pnas.2009072117
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author Williams, Ian
Lee, Sangyoon
Apriceno, Azzurra
Sear, Richard P.
Battaglia, Giuseppe
author_facet Williams, Ian
Lee, Sangyoon
Apriceno, Azzurra
Sear, Richard P.
Battaglia, Giuseppe
author_sort Williams, Ian
collection PubMed
description Glucose is an important energy source in our bodies, and its consumption results in gradients over length scales ranging from the subcellular to entire organs. Concentration gradients can drive material transport through both diffusioosmosis and convection. Convection arises because concentration gradients are mass density gradients. Diffusioosmosis is fluid flow induced by the interaction between a solute and a solid surface. A concentration gradient parallel to a surface creates an osmotic pressure gradient near the surface, resulting in flow. Diffusioosmosis is well understood for electrolyte solutes, but is more poorly characterized for nonelectrolytes such as glucose. We measure fluid flow in glucose gradients formed in a millimeter-long thin channel and find that increasing the gradient causes a crossover from diffusioosmosis-dominated to convection-dominated flow. We cannot explain this with established theories of these phenomena which predict that both scale linearly. In our system, the convection speed is linear in the gradient, but the diffusioosmotic speed has a much weaker concentration dependence and is large even for dilute solutions. We develop existing models and show that a strong surface–solute interaction, a heterogeneous surface, and accounting for a concentration-dependent solution viscosity can explain our data. This demonstrates how sensitive nonelectrolyte diffusioosmosis is to surface and solution properties and to surface–solute interactions. A comprehensive understanding of this sensitivity is required to understand transport in biological systems on length scales from micrometers to millimeters where surfaces are invariably complex and heterogeneous.
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spelling pubmed-75682922020-10-27 Diffusioosmotic and convective flows induced by a nonelectrolyte concentration gradient Williams, Ian Lee, Sangyoon Apriceno, Azzurra Sear, Richard P. Battaglia, Giuseppe Proc Natl Acad Sci U S A Physical Sciences Glucose is an important energy source in our bodies, and its consumption results in gradients over length scales ranging from the subcellular to entire organs. Concentration gradients can drive material transport through both diffusioosmosis and convection. Convection arises because concentration gradients are mass density gradients. Diffusioosmosis is fluid flow induced by the interaction between a solute and a solid surface. A concentration gradient parallel to a surface creates an osmotic pressure gradient near the surface, resulting in flow. Diffusioosmosis is well understood for electrolyte solutes, but is more poorly characterized for nonelectrolytes such as glucose. We measure fluid flow in glucose gradients formed in a millimeter-long thin channel and find that increasing the gradient causes a crossover from diffusioosmosis-dominated to convection-dominated flow. We cannot explain this with established theories of these phenomena which predict that both scale linearly. In our system, the convection speed is linear in the gradient, but the diffusioosmotic speed has a much weaker concentration dependence and is large even for dilute solutions. We develop existing models and show that a strong surface–solute interaction, a heterogeneous surface, and accounting for a concentration-dependent solution viscosity can explain our data. This demonstrates how sensitive nonelectrolyte diffusioosmosis is to surface and solution properties and to surface–solute interactions. A comprehensive understanding of this sensitivity is required to understand transport in biological systems on length scales from micrometers to millimeters where surfaces are invariably complex and heterogeneous. National Academy of Sciences 2020-10-13 2020-09-28 /pmc/articles/PMC7568292/ /pubmed/32989158 http://dx.doi.org/10.1073/pnas.2009072117 Text en Copyright © 2020 the Author(s). Published by PNAS. https://creativecommons.org/licenses/by-nc-nd/4.0/ https://creativecommons.org/licenses/by-nc-nd/4.0/This open access article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND) (https://creativecommons.org/licenses/by-nc-nd/4.0/) .
spellingShingle Physical Sciences
Williams, Ian
Lee, Sangyoon
Apriceno, Azzurra
Sear, Richard P.
Battaglia, Giuseppe
Diffusioosmotic and convective flows induced by a nonelectrolyte concentration gradient
title Diffusioosmotic and convective flows induced by a nonelectrolyte concentration gradient
title_full Diffusioosmotic and convective flows induced by a nonelectrolyte concentration gradient
title_fullStr Diffusioosmotic and convective flows induced by a nonelectrolyte concentration gradient
title_full_unstemmed Diffusioosmotic and convective flows induced by a nonelectrolyte concentration gradient
title_short Diffusioosmotic and convective flows induced by a nonelectrolyte concentration gradient
title_sort diffusioosmotic and convective flows induced by a nonelectrolyte concentration gradient
topic Physical Sciences
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7568292/
https://www.ncbi.nlm.nih.gov/pubmed/32989158
http://dx.doi.org/10.1073/pnas.2009072117
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