On diffusion in organized assemblies and in biological membranes

Article type: Review Article

Authors: Andre, J.C.^a | Bouchy, M.^a | Donner, M.^b

Affiliations: [a] GRAPP de l’UA 328 du CNRS, ENSIC - INPL, 1 rue Grandville, 54042 Nancy Cedex, France | [b] U 284 INSERM Plateau de Brabois, 54511 Vandoeuvre les Nancy Cedex, France

Note: [] Invited by Editor-in-Chief A.L. Copley.

Abstract: The following paper is a brief presentation of problems related to the concepts of diffusion coefficient D and so-called viscosity η used to characterize the cohesion of biological membranes. The first approach to this problem is a recall of the definition of D and η in liquids. It appears that the models developed with exogenous probes to account for the diffusion-viscosity relationship are not verified in membranes. The existence of complex diffusional mechanisms, the influence of the size of the probe are presented. The results of a model calculation suggest that there is no direct correlation other than great simplifications, between the diffusion coefficient and viscosity. The calculations are then extended to actual biological assemblies and the influence of proteins on the motion of the probe considered. The limitations of the methods involving exogeneous probes for determining the cohesion of biological membranes are discussed.

Keywords: Biological membranes, viscosity, diffusion coefficient

DOI: 10.3233/BIR-1987-24216

Journal: Biorheology, vol. 24, no. 2, pp. 237-272, 1987