Chemical modification of cellulosic membranes and their blood compatibility.

Blood compatibility is determined by interactions at the blood-material interface that depend on the material surface chemical structure. Through selective modifications of the chemically reactive hydroxyl groups of cellulose, the aim was to improve the biocompatibility of cellulose membranes. The number of potentially reactive hydroxyl groups on the cellulose membrane surface were reduced through isocyanate cross-links or through the introduction of hydrophilic, hydrophobic, or ionic functionalities by graft copolymerization. To assess blood compatibility, levels of C3a desArg were determined in plasma after membrane contact. Using the electrophoretic mobility test, the release of cytokines were measured after in-vitro incubation of mononuclear cells with membranes. Adsorption of 131J-human fibrinogen was additionally investigated. With respect to the biocompatibility parameters selected, the modified cellulose membranes show improved in-vitro blood compatibility in comparison to unmodified cellulose membranes.