PARTIALLY CATIONIZED CELLULOSE FOR NON-THROMBOGENIC MEMBRANE IN THE PRESENCE OF HEPARIN AND ENDOTHELIAL-CELL-SURFACE-HEPARANSULFATE (ES-HS)

Partially cationized cellulose derivatives (DS 0.01-0.1) have been synthesized by modification of cotton, Cuprophan(R) and cellulose dialysis membranes with 3-chloro-2-hydroxypropyltrimethyl-ammoniumchloride and used for the following studies: Adsorption and desorption studies of heparin on partially cationized cellulose in NaHCO3-solution show that heparin can be drastically enriched with increase of the DS of cellulose, whereas imidazole buffer and a pyridine-water mixture (DS 0.06) desorb heparin partially or completely. When partially cationized cellulose was used under suitable conditions for heparin enrichment and additionally four different crosslinking reagents and different reaction steps were applied and compared with non-cationized cellulose, the ionic fixation of heparin was ten to fifty times higher compared with non-cationized cellulose. When tested with blood partially cationized cellulose showed a high platelet adhesion whereas endothelial-cell-surface-heparansulfate (ES-HS), isolated from bovine aorta and immobilized on partially cationized cellulose, was completely inert to platelet adhesion measured in a modified Baumgartner chamber. The latter result seems to give a new promising concept for the synthesis of biomaterials, e.g. membranes with nonthrombogenic surfaces similar to surfaces of blood vessels in nature because the isolation procedure of ES-HS and immobilization of ES-HS on polymer surfaces does not change the inertness of ES-HS to platelet adhesion.