TY - JOUR
T1 - Nonuniform Crowding Enhances Transport
AU - Collins, Matthew
AU - Mohajerani, Farzad
AU - Ghosh, Subhadip
AU - Guha, Rajarshi
AU - Lee, Tae Hee
AU - Butler, Peter J.
AU - Sen, Ayusman
AU - Velegol, Darrell
N1 - Funding Information:
The work was supported by Penn State MRSEC funded by the National Science Foundation (DMR-1420620) and by NSF CBET-1603716.
Funding Information:
The work was supported by Penn State MRSEC funded by the National Science Foundation (DMR-1420620) and by NSF CBET-1603716.
Publisher Copyright:
Copyright © 2019 American Chemical Society.
PY - 2019/8/27
Y1 - 2019/8/27
N2 - The cellular cytoplasm is crowded with macromolecules and other species that occupy up to 40% of the available volume. Previous studies have reported that for high crowder molecule concentrations, colloidal tracer particles have a dampened diffusion due to the higher solution viscosity. However, these studies employed uniform distributions of crowder molecules. We report a scenario, previously unexplored experimentally, of increased tracer transport driven by a nonuniform concentration of crowder macromolecules. In gradients of a polymeric crowder, tracer particles undergo transport several times higher than that of their bulk diffusion rate. The direction of the transport is toward regions of lower crowder concentration. Mechanistically, hard-sphere interactions and the resulting volume exclusion between the tracer and crowder increase the effective diffusion by inducing a convective motion of tracers, which we explain through modeling. Strikingly, soft deformable particles show even greater enhancement in transport in crowder gradients compared to similarly sized hard particles. Overall, this demonstration of enhanced transport in nonuniform distributions of crowders is anticipated to clarify aspects of multicomponent intracellular transport.
AB - The cellular cytoplasm is crowded with macromolecules and other species that occupy up to 40% of the available volume. Previous studies have reported that for high crowder molecule concentrations, colloidal tracer particles have a dampened diffusion due to the higher solution viscosity. However, these studies employed uniform distributions of crowder molecules. We report a scenario, previously unexplored experimentally, of increased tracer transport driven by a nonuniform concentration of crowder macromolecules. In gradients of a polymeric crowder, tracer particles undergo transport several times higher than that of their bulk diffusion rate. The direction of the transport is toward regions of lower crowder concentration. Mechanistically, hard-sphere interactions and the resulting volume exclusion between the tracer and crowder increase the effective diffusion by inducing a convective motion of tracers, which we explain through modeling. Strikingly, soft deformable particles show even greater enhancement in transport in crowder gradients compared to similarly sized hard particles. Overall, this demonstration of enhanced transport in nonuniform distributions of crowders is anticipated to clarify aspects of multicomponent intracellular transport.
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U2 - 10.1021/acsnano.9b02811
DO - 10.1021/acsnano.9b02811
M3 - Article
C2 - 31291087
AN - SCOPUS:85071711127
VL - 13
SP - 8946
EP - 8956
JO - ACS Nano
JF - ACS Nano
SN - 1936-0851
IS - 8
ER -