The medical material contains heparinized collagen in which heparin has been bonded to protamine covalently fixed on collagen, and, owing to its excellent compatibility with living bodies, especially, its superb antithrombotic property, can be suitably used as a substituent material for tissues or organs...http://www.google.com/patents/US4704131?utm_source=gb-gplus-sharePatent US4704131 - Medical materials
