PROTEINS TRANSPORT THROUGH CHARGED POROUS MEMBRANES

A model for the diffusive and convective transport of rigid, spherical solutes through slit-shaped pores is used to examine electrostatic ef fects on solute exclusion by charged pores. This model includes steric and hydrodynamic drag, repulsive electrostatic interactions and pore size distribution represented as a log-normal probability density func tion. Analytical expressions for the effective diffusion coefficient a nd for the asymptotic sieving coefficient are obtained. To test theore tical predictions, experimental values of these coefficients are deter mined from diffusion and convection experiments conducted with globula r proteins at various ionic strengths. Ultrafiltration and microfiltra tion membranes pore sizes are characterized after sieving measurements of neutral dextrans. Experimental and theoretical results are in fair ly good agreement except for the microfiltration membrane.