title: Platelet repellent properties of hydrogel coatings on polyurethane-coated glass surfaces.
abstract: Thromboembolism is a severe complication in patients with ventricular assist devices. Interactions of platelets with the artificial surface and pathological blood flow conditions could contribute to thrombus formation. Previous studies suggested that strongly swellable polymer coatings prepared from various poly(N-alkyl acrylamides) are bioinert as they repel proteins and cells. In this study, we tested structurally similar polymer coatings with varying degrees of crosslinking and swelling to explore if the bioinert character of such coatings is also valid under whole blood perfusion and shear stress. Glass substrates coated with medical grade polyurethane (PU) were modified with surface-attached poly(N-alkyl acrylamide) layers, which differed in crosslinking and in swelling. Slides were perfused with human blood containing fluoresceinated platelets at a shear rate of 1500 s for 3 minutes. Noncoated and PU-coated glass slides served as a reference for thrombogenic surfaces. We detected severe platelet adhesion on the reference surfaces. There was no platelet adhesion on poly(N-alkyl acrylamide) coatings with a swelling factor above 1.5-2 (p < 0.001 compared with PU). A lower swelling factor resulted in severe platelet adhesion. Different degrees of crosslinking ranging from 1% to 10% did not reverse platelet repellent properties of the representative polymer tested (p < 0.001 compared with PU).
authors.affiliation: From the *Department of Cardiovascular Surgery, Heart Center Freiburg University, Freiburg, Germany; †Department of Medicine, Division of Cardiology, Tokai University School of Medicine, Isehara, Japan; ‡Department of Microsystems Engineering (IMTEK), Laboratory for Chemistry and Physics of Interfaces, University of Freiburg, Freiburg, Germany; and §Department of Pediatrics and Adolescent Medicine, Laboratory for Hemostaseology, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Maral
authors.initials: M
authors.lastname: Baghai
authors.forename: Noriko
authors.initials: N
authors.lastname: Tamura
authors.forename: Friedhelm
authors.initials: F
authors.lastname: Beyersdorf
authors.forename: Michael
authors.initials: M
authors.lastname: Henze
authors.forename: Oswald
authors.initials: O
authors.lastname: Prucker
authors.forename: Jürgen
authors.initials: J
authors.lastname: Rühe
authors.forename: Shinya
authors.initials: S
authors.lastname: Goto
authors.forename: Barbara
authors.initials: B
authors.lastname: Zieger
authors.forename: Claudia
authors.initials: C
authors.lastname: Heilmann
mesh_terms: D000327:Adsorption; D001792:Blood Platelets; D006353:Heart-Assist Devices / Q000009:adverse effects; D006801:Humans; D020100:Hydrogels; D010973:Platelet Adhesiveness; D011673:Pulsatile Flow; D033081:Shear Strength; D013499:Surface Properties; D013923:Thromboembolism / Q000209:etiology / Q000517:prevention & control*
chemical_list: D020100:Hydrogels