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Drift of a semi-permeable vesicle through an osmotic gradient: anomalous velocity amplification due to a proximate wall

Published online by Cambridge University Press:  13 May 2025

Ehud Yariv*
Affiliation:
Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
*
Corresponding author: Ehud Yariv, yarivehud@gmail.com

Abstract

A spherical vesicle is made up of a liquid core bounded by a semi-permeable membrane that is impermeable to solute molecules. When placed in an externally imposed gradient of solute concentration, the osmotic pressure jump across the membrane results in an inward trans-membrane solvent flux at the solute-depleted side of the vesicle, and and outward flux in its solute-enriched side. As a result, a freely suspended vesicle drifts down the concentration gradient, a phenomenon known as osmophoresis. An experimental study of lipid vesicles observed drift velocities that are more than three orders of magnitude larger than the linearised non-equilibrium prediction (Nardi et al., Phys. Rev. Lett., vol. 82, 1999, pp. 5168–5171). Inspired by this study, we analyse osmophoresis of a vesicle in close proximity to an impermeable wall, where the vesicle–wall separation $a\delta$ is small compared with the vesicle radius $a$. Due to intensification of the solute concentration gradient in the narrow gap between the membrane and the wall, the ‘osmophoretic’ force and torque on a stationary vesicle scale as an irrational power, $1/\sqrt {2}-1\ (\approx -0.29289\ldots )$, of $\delta$. Both the rectilinear velocity $\mathcal V$ and the angular velocity $\unicode {x1D6FA}$ of a freely suspended vesicle scale as the ratio of that power to $\ln \delta$. In contrast to the classical problem of sedimentation parallel to a wall, where the ratio $a\unicode {x1D6FA}/\mathcal V$ approaches $1/4$ as $\delta \to 0$, here the ratio approaches unity, as though the vesicle performs pure rigid-body rolling without slippage. Our approximations are in excellent agreement with hitherto unexplained numerical computations in the literature.

Information

Type
JFM Papers
Copyright
© The Author(s), 2025. Published by Cambridge University Press

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References

Anderson, J.L. 1983 Movement of a semipermeable vesicle through an osmotic gradient. Phys. Fluids 26 (10), 28712879.CrossRefGoogle Scholar
Anderson, J.L., Lowell, M.E. & Prieve, D.C. 1982 Motion of a particle generated by chemical gradients. Part 1. Non-electrolytes. J. Fluid Mech. 117 (1), 107121.CrossRefGoogle Scholar
Bloom, M., Evans, E. & Mouritsen, O.G. 1991 Physical properties of the fluid lipid-bilayer component of cell membranes: a perspective. Q. Rev. Biophys. 24 (3), 293397.CrossRefGoogle ScholarPubMed
Brandão, R. 2024 Isotropically active particle closely fitting in a cylindrical channel: spontaneous motion at small Péclet numbers. J. Fluid Mech. 980, A2.CrossRefGoogle Scholar
Brenner, H. 1964 The Stokes resistance of an arbitrary particle. IV. Arbitrary fields of flow. Chem. Engng Sci. 19 (10), 703727.CrossRefGoogle Scholar
Chen, P.Y. & Keh, H.J. 2003 Boundary effects on osmophoresis: motion of a spherical vesicle parallel to two plane walls. Chem. Engng Sci. 58 (19), 44494464.CrossRefGoogle Scholar
Cooley, M.D.A. & O’Neill, M.E. 1968 On the slow rotation of a sphere about a diameter parallel to a nearby plane wall. J. Inst. Appl. Maths 4 (2), 163173.CrossRefGoogle Scholar
De Groot, S.R. & Mazur, P. 2013 Non-Equilibrium Thermodynamics. Courier Corporation.Google Scholar
Dean, W.R. & O’Neill, M.E. 1963 A slow motion of a viscous liquid caused by the rotation of a solid sphere. Mathematika 10 (1), 1324.CrossRefGoogle Scholar
Goldman, A.J., Cox, R.G. & Brenner, H. 1967 Slow viscous motion of a sphere parallel to a plane wall. I. Motion through a quiescent fluid. Chem. Engng Sci. 22 (4), 637651.CrossRefGoogle Scholar
Gordon, L.G.M. 1981 Osmophoresis. J. Phys. Chem. 85 (12), 17531755.CrossRefGoogle Scholar
Gu, Y., Tran, L., Lee, S., Zhang, J. & Bishop, K.J.M. 2023 Convection confounds measurements of osmophoresis for lipid vesicles in solute gradients. Langmuir 39 (3), 942948.CrossRefGoogle Scholar
Happel, J. & Brenner, H. 1965 Low Reynolds Number Hydrodynamics. Prentice-Hall.Google Scholar
Jeffrey, D.J. 1996 Some basic principles in interaction calculations. In Sedimentation of Small Particles in a Viscous Fluid (ed. Torry, E.M.), chap. 4, pp. 97124. Computational Mechanics Publications.Google Scholar
Kedem, O. & Katchalsky, A. 1958 Thermodynamic analysis of the permeability of biological membranes to non-electrolytes. Biochim. Biophys. Acta 27, 229246.CrossRefGoogle ScholarPubMed
Keh, H.J. & Chen, S.B. 1988 Electrophoresis of a colloidal sphere parallel to a dielectric plane. J. Fluid Mech. 194 (1), 377390.CrossRefGoogle Scholar
Keh, H.J. & Yang, F.R. 1993 Boundary effects on osmophoresis: motion of a vesicle in an arbitrary direction with respect to a plane wall. Chem. Engng Sci. 48 (20), 35553563.CrossRefGoogle Scholar
Kim, S. & Karrila, S.J. 2005 Microhydrodynamics: Principles and Selected Applications. Dover.Google Scholar
Leal, L.G. 2007 Advanced Transport Phenomena: Fluid Mechanics and Convective Transport Processes. Cambridge University Press.CrossRefGoogle Scholar
Li, C., Boileau, A.J., Kung, C. & Adler, J. 1988 Osmotaxis in Escherichia coli. Proc. Natl Acad. Sci. USA 85 (24), 94519455.CrossRefGoogle ScholarPubMed
Liang, Q., Zhao, C. & Yang, C. 2015 Enhancement of electrophoretic mobility of microparticles near a solid wall – experimental verification. Electrophoresis 36 (5), 731736.CrossRefGoogle Scholar
Lipchinsky, A. 2015 Osmophoresis – a possible mechanism for vesicle trafficking in tip-growing cells. Phys. Biol. 12 (6), 066012.CrossRefGoogle ScholarPubMed
Masoud, H. & Stone, H.A. 2019 The reciprocal theorem in fluid dynamics and transport phenomena. J. Fluid Mech. 879, P1.CrossRefGoogle Scholar
Mathai, J.C., Tristram-Nagle, S., Nagle, J.F. & Zeidel, M.L. 2008 Structural determinants of water permeability through the lipid membrane. J. Gen. Physiol. 131 (1), 6976.CrossRefGoogle ScholarPubMed
Nardi, J., Bruinsma, R. & Sackmann, E. 1999 Vesicles as osmotic motors. Phys. Rev. Lett. 82 (25), 51685171.CrossRefGoogle Scholar
O’Neill, M.E. 1964 A slow motion of a viscous liquid caused by a slowly moving solid sphere. Mathematika 11 (1), 6474.Google Scholar
O’Neill, M.E. & Stewartson, K. 1967 On the slow motion of a sphere parallel to a nearby plane wall. J. Fluid Mech. 27 (4), 705724.CrossRefGoogle Scholar
Peng, Z., Zhou, T. & Brady, J.F. 2022 Activity-induced propulsion of a vesicle. J. Fluid Mech. 942, A32.CrossRefGoogle Scholar
Pope, C.G. 1982 Investigation of osmophoresis. J. Phys. Chem. 86 (10), 18691870.CrossRefGoogle Scholar
Schnitzer, O. & Yariv, E. 2012 Macroscale description of electrokinetic flows at large zeta potentials: nonlinear surface conduction. Phys. Rev. E 86 (2), 021503.CrossRefGoogle Scholar
Solomentsev, Y., Velegol, D. & Anderson, J.L. 1997 Conduction in the small gap between two spheres. Phys. Fluids 9 (5), 12091217.CrossRefGoogle Scholar
Xuan, X., Ye, X. & Li, D. 2005 Near-wall electrophoretic motion of spherical particles in cylindrical capillaries. J. Colloid Interface Sci. 289 (1), 286290.CrossRefGoogle ScholarPubMed
Yariv, E. 2016 a The electrophoretic mobilities of a circular cylinder in close proximity to a dielectric wall. J Fluid Mech. 804, R5.CrossRefGoogle Scholar
Yariv, E. 2016 b Wall-induced self-diffusiophoresis of active isotropic colloids. Phys. Rev. Fluids 1 (3), 032101.CrossRefGoogle Scholar
Yariv, E. & Brenner, H. 2003 Near-contact electrophoretic motion of a sphere parallel to a planar wall. J. Fluid Mech. 484, 85111.CrossRefGoogle Scholar