Heparin binding and release properties of DEAE cellulose membranes

Two cellulose-based membranes, containing 5 and 20% N, N-diethyl-aminoethyl cellulose (DEAE) respectively, were investigated for ionic attachment of heparin and heparin release. Heparinization was achieved by recirculation of a heparin-containing glycine buffer over each membrane. Heparin was determined by chemical analysis or by 99mTc labelling. The heparin uptake was shown to be linearly dependent on the heparin content in the contacting fluid. Heparin release was studied by contacting heparinized membranes with saline, glycine buffer, phosphate buffer and plasma. Incubation with plasma brought about the release of 50% of the attached heparin. Crosslinking of the heparinized membrane with glutaraldehyde reduced the heparin release by one half. The release reaction is more critical in the case of increased heparin uptake and a more efficient immobilization of heparin appears necessary.