Importance

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Abstract

A bio-active material such as heparin, urokinase or streptokinase is bonded via a hydrophilic spacer to a functionality on the surface of a hydrophobic, bio-compatible polymeric substrate to provide a coating of the bio-active material on the surface. The substrate surface is preferably the surface of an implantable medical device such as a vascular graft. An amine and/or hydroxyl functionality on the substrate surface is reacted with an isocyanate group at an end of the hydrophilic spacer to bond the spacer to the substrate, and the bio-active material is reacted with an isocyanate group at another end of the spacer to bond the bio-active material to the spacer. Polymeric substrates include expanded polytetrafluoroethylene and polyethylene terephthalate, and the hydroxyl and/or amine functionality may be provided on the substrate surface by plasma glow discharge. A preferred spacer is an isocyanate end-blocked poly(ethylene oxide). Reaction of the functionality of the substrate with the isocyanate group of the spacer may be catalyzed with dibutyltindilaurate, and reaction of the bio-active material with the isocyanate group of the spacer may be catalyzed with 1-(3 -dimethylaminopropyl)-3-ethylcarbodiimide.

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First Claim