CELLULOSE-ESTER AS MEMBRANE MATERIALS FOR HEMODIALYSIS

The majority of dialysis membranes are fabricated from regenerated unm odified cellulose. This standard type of cellulosic membrane is freque ntly under attack because of its alleged lack of biocompatibility. Rec ent developments, however, have proven that a chemical modification of the reactive surface groups of regenerated cellulose, the hydroxyl-gr oups, limits the complement-activating potential of these materials an d thus improves its blood-compatibility. We extended the idea of modif ying cellulose for improved blood-compatibility to a series of differe nt cellulose esters. Special focus was directed towards the question w hether a variation of the type of substituent and degree of substituti on could influence the blood-compatibility pattern of these materials: the analysis of blood-compatibility profiles showed a direct dependen cy on the type of substituent and the degree of substitution (DS). As an example, if was found that the DS, necessary for a complete reducti on of complement activation, decreases with increasing chain lengths o f aliphatic substituents. Optimal degrees of substitution are characte ristic of the type of substituents and enable us to tailor materials s pecifically for optimized blood compatibility.