ABSTRACT
This chapter is concerned with polymer membranes used in clinical applications. The role of such membranes as biomaterials is to act as an imperfect barrier and thereby permit the transfer of solute, liquid, or gas in contact with blood during clinical conditions. The separation processes relevant to the use of polymer membranes in extra-corporeal blood purification are dialysis, osmosis, and ultrafiltration. Dialysis, osmosis, and ultrafiltration are the separation processes which permit the utilization of polymer membranes in extracorporeal blood purification. Polymer membranes used in extracorporeal blood purification must comply with requirements of permeability, mechanical strength, and blood compatibility and it is important to consider each of these properties in turn prior to an examination of polymer membranes proposed for clinical use. Regenerated cellulose membranes form the logical starting point in a consideration of membrane systems. With respect to solute transport characteristics, cellulose membranes appear to act as sieves or microporous barriers.
