https://doi.org/10.1140/epje/s10189-024-00419-6
Regular Article - Soft Matter
A hard sphere model for single-file water transport across biological membranes
Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Road, 08854-8087, Piscataway, NJ, USA
Received:
21
August
2023
Accepted:
22
March
2024
Published online:
15
April
2024
We use Gürsey’s statistical mechanics of a one-dimensional fluid to find a formula for the 
ratio in the transport of hard spheres across a membrane through a narrow channel that can accommodate molecular movement only in single file. 
is the membrane permeability for osmotic flow and 
the permeability for exchange across the membrane in the absence of osmotic flow. The deviation of the ratio from unity indicates the degree of cooperative transport relative to ordinary diffusion of independent molecules. In contrast to an early idea that must be equal to the number of molecules in the channel, regardless of the physical nature of the interactions among the molecules, we find a functional dependence on the fractional occupancy of the length of the channel by the hard spheres. We also attempt a random walk calculation for individually, which gives a result for as well when combined with the ratio.
© The Author(s) 2024
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