SOLUTE WASHOUT EXPERIMENTS FOR CHARACTERIZING MASS-TRANSPORT IN HOLLOW-FIBER IMMUNOISOLATION MEMBRANES

The transport characteristics of immunoisolation membranes can have a critical effect on the design of hybrid artificial organs and cell the rapies. However, it has been difficult to quantitatively evaluate the desired transport properties of different hollow fiber membranes due t o bulk mass transfer limitations in the fiber lumen and annular space. An attractive alternative to existing methodologies is to use the rat e of solute removal or ''washout'' from the annular space during const ant flow perfusion through the fiber lumen. Experimental washout curve s were obtained for glucose and a 10 kD dextran in two different hollo w fiber devices. Data were analyzed using a theoretical model which ac counts for convective and diffusive transport in the lumen, membrane, and annular space. The model was in good agreement with the experiment al results and provided an accurate measure of the effective membrane diffusion coefficient for both small and large solutes. This approach should prove useful in theoretical analyses of solute transport and pe rformance of hollow fiber artificial organs. (C) 1998 Biomedical Engin eering Society.