title: Covalent immobilization of hirudin improves the haemocompatibility of polylactide-polyglycolide in vitro.
abstract: A biodegradable polymer, poly(D,L-lactide-co-glycolide) RESOMER RG756, was modified by surface immobilization of recombinant hirudin (r-Hir) with glutaraldehyde as coupling reagent to improve the blood contacting properties of the polymer. The activity of immobilized hirudin on the polymer was estimated by a chromogenic assay to about 2.5 ATU r-Hir cm-2. The improvement of the haemocompatibility of the modified RG756 was evaluated in terms of platelet adhesion/activation, whole blood clotting times and clot formation rate. Fluorescence microscopy revealed that surface modification with r-Hir resulted in decreased platelet adhesion and activation. An ELISA for P-selectin, a marker of platelet activation, was used to confirm this result. Clotting time experiments demonstrated significantly prolonged non-activated partial thromboplastin times, and a decreased clot formation rate of whole blood in contact with r-Hir modified RG756 compared with the plain polymer. Comparison of immobilized r-Hir with bound heparin yielded equivalent improvement of blood-contacting properties of the investigated polymers. These in vitro investigations indicate that the immobilization of r-Hir on RG756 is a useful method to improve the blood contacting properties of polylactides/polyglycolides and other polymers as well.
authors.affiliation: Institut für Röntgendiagnostik, Bereich Interventionsradiologie/Angiologie, Universitätsklinikum Charité, Humboldt-Universität zu Berlin, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Seifert
authors.forename: P
authors.initials: P
authors.lastname: Romaniuk
authors.forename: T
authors.initials: T
authors.lastname: Groth
mesh_terms: D000991:Antithrombins / Q000737:chemistry* / Q000494:pharmacology*; D001672:Biocompatible Materials / Q000737:chemistry* / Q000494:pharmacology*; D001777:Blood Coagulation / Q000187:drug effects; D006629:Hirudins / Q000097:blood* / Q000737:chemistry* / Q000494:pharmacology; D006801:Humans; D019344:Lactic Acid / Q000737:chemistry* / Q000494:pharmacology*; D008856:Microscopy, Fluorescence; D019007:P-Selectin / Q000032:analysis; D015539:Platelet Activation / Q000187:drug effects; D010973:Platelet Adhesiveness / Q000187:drug effects; D011100:Polyglycolic Acid / Q000737:chemistry* / Q000494:pharmacology*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry* / Q000494:pharmacology*; D014914:Whole Blood Coagulation Time
chemical_list: D000991:Antithrombins; D001672:Biocompatible Materials; D006629:Hirudins; D019007:P-Selectin; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid