Immobilization of heparin to EDC/NHS-crosslinked collagen. Characterization and in vitro evaluation

Wissink, M.J.B. and Beernink, R. and Pieper, J.S. and Poot, A.A. and Engbers, G.H.M. and Beugeling, T. and Aken van, W.G. and Feijen, J. (2001) Immobilization of heparin to EDC/NHS-crosslinked collagen. Characterization and in vitro evaluation. Biomaterials, 22 (2). pp. 151-163. ISSN 0142-9612

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Abstract:	In the present study, heparin immobilization to a non-cytotoxic crosslinked collagen substrate for endothelial cell seeding was investigated. Crosslinking of collagen using N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS) resulted in a material containing 14 free primary amino groups per 1000 amino acid residues (E/N14C). At a fixed molar ratio NHS : EDC of 0.6, the amount of heparin covalently immobilized to E/N14C increased with increasing molar ratios of EDC to heparin carboxylic acid groups (Hep-COOH), to a maximum of approximately 5–5.5 wt% at a ratio of 2. Upon incubation in cell culture medium of endothelial cells, 4 to 7% of the immobilized heparin was released during 11 days. Immobilization of increasing amounts of heparin to E/N14C progressively reduced activation of contact activation proteases. Optimal anticoagulant activity, as measured by thrombin inhibition, was obtained after heparin immobilization using a ratio of EDC to Hep-COOH of 0.2–0.4 (14–20 mg heparin immobilized per gram of collagen). Platelets deposited to (heparinized) E/N14C showed only minor spreading and aggregation, although heparin immobilization slightly increased the number of adherent platelets. The results of this study suggest that heparin immobilization to EDC/NHS-crosslinked collagen may improve the in vivo blood compatibility of this material.
Item Type:	Article
Copyright:	© 2001 Elsevier
Faculty:	Science and Technology (TNW)
Research Group:	Biomaterials Science and Technology (BST) Polymer Chemistry and BioMaterials (PBM)
Link to this item:	http://purl.utwente.nl/publications/74443
Official URL:	http://dx.doi.org/10.1016/S0142-9612(00)00164-2
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