An in vitro study of heparin-immobilized poly(ethylene-graft-vinylacetate)and poly(ethylene-graft-vinylpyridine)

Polyethylene (PE) was modified by radiation-induced grafting of vinyl aceta te (VAc) and vinyl pyridine (VP), followed by heparinization of the surface . The unmodified, the grafted, and the heparin-immobilized samples were stu died with X-ray photoelectron spectroscopy. The heparinized samples were al so studied by Laser Scanning Confocal Microscopy and by the toluidine blue method. The biological activity of heparin against thrombin formation was e valuated by the chromogenic method. The graft-copolymerization of PE with V Ac or VP, as well as the heparin immobilization were successfully carried o ut. The heparin was strongly attached to the VP-grafter PE, but underwent s low release when immobilized on the hydrolyzed VAc-grafter PE. The grafted and heparinized materials showed no toxicity when examined by in vitro cell studies, and the immobilized heparin retained its biological activity.