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Poly(DL-lactic acid) film surface modification with heparin for improving hemocompatibility of blood-contacting bioresorbable devices.

This work describes a simple method to immobilize heparin by covalent bonding to the surface of poly(lactic acid) film with the aim of showing improved hemocompatibility. Carboxyl groups present in heparin molecules were activated by reaction with N-hydroxy-succinimide and allowed to react with free amino groups created at the surface of poly(DL-lactic acid) films by controlled aminolysis. Contact angle measurements and XPS analysis confirmed the binding. Quantification was determined by radioactivity using heparin labeled with tritium. The surface exhibited anti factor Xa activity, thus confirming the presence of bounded heparin that kept some biological activity. Finally platelets adhesion showed less platelet adhesion on heparin modified films as well as preserved morphology.