Forced Diffusion Through an Elastic Gel Membrane

Abstract

The objectives of the experiment were (a) to establish general empirical and theoretical techniques for the in vitro analysis of diffusion through biological membranes, and (b) to provide characteristic data on gel membranes for possible application as biological filtering septa. Experimental procedures are described for the manufacture of molded Agarose gel membranes of 0.025 cm uniform thickness and 113.2 sq cm area. Flow rates through the gel membranes were determined and reported for various values of temperature and impressed pressure and for gel concentrations of both six percent and eight percent. Water was the permeant for all tests. The gel membranes were treated as elastic structures, and it was determined that the flow was described by Darcy’s law. A simple capillaric model was postulated for the elastic structure and used for the correlation of the flow rate data. For vanishing rates of flow, permeabilities were reported as 11.60 × 10−14 sq cm for the six percent gel and 8.68 × 10−14 sq cm for the eight percent gel. Characteristic diameters of the gel pores were reported as 207 Angstroms for the six percent and 183.3 Angstroms for the eight percent gel. Void volume and pore density were also reported for each.