Interpretation of passive permeability measurements on lipid-bilayer vesicles. Effect of fluctuations.
A stochastic model for migration dynamics of solute molecules from the bulk aqueous phase to the intravesicular water pool is developed with a goal to interpret recent passive permeability measurements of bilayer membranes. Previously neglected fluctuations of the number of solubilized species in the inner water pool of a vesicle are naturally incorporated into the model. For a homogeneous one-phase bilayer, the model predicts exponential long-time asymptotics of the migration dynamics with a rate constant given by a sum of the frequencies of exit and entry of a solute molecule from/into the intravesicular water pool into/from the bulk aqueous phase. The long-time constant is directly related to the membrane permeability.
Barzykin
A V
AV
Department of Physical Chemistry, National Institute of Materials and Chemical Research, Tsukuba, Ibaraki, Japan. barzykin@nimc.go.jp
Tachiya
M
M
D002463:Cell Membrane Permeability; D007473:Ion Channels / Q000378:metabolism; D007700:Kinetics; D008051:Lipid Bilayers / Q000378:metabolism*; D008954:Models, Biological; D013269:Stochastic Processes; D014867:Water / Q000378:metabolism
D007473:Ion Channels; D008051:Lipid Bilayers; D014867:Water