A simple method to heparinize biological materials.

A new method was developed inducing antithrombogenicity to biologic materials. A basic protein, protamine, was used to increase heparin binding to collagenous materials. Protamine sulfate solution was poured into a collagen-rich material (porcine ureter). The protamine adsorbed to the collagen was then cross-linked to the material by glutaraldehyde. The collagen-protamine complex was then interacted with a heparin solution to ionically bind heparin to the material. The amount and the distribution of the bound heparin can be controlled by changing the protamine fixation to the material. A heparinized porcine ureter as a vascular substitute showed excellent antithrombogenicity in experimental animal studies. This method is expected to be used as method for developing antithrombogenic artificial organs, and as a method for the development of antiadhesive membranes.