Hyaluronan (hyaluronic acid, HA) was immobilized onto the surface of amino-functionalized polyurethane films with the goal of obtaining a novel kind of biomaterial which had the potential in blood-contacting applications. The amino-functionalized polyurethane was prepared by synthesized acidic polyurethane whose pendant carboxyl groups were treated with an excess amount of 1,3-diaminopropane in the presence of N,N-carbonyldiimidazole (CDI). Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy (RS), scanning electron microscopy (SEM), and water contact angle measurement were used to confirm the surface changes at each step of treatment, both in morphologies and chemical compositions. APTT and PT results showed that HA immobilization could prolong the blood coagulation time, thus HA-immobilized polyurethane (PU-HA) exhibited improved blood compatibility. Cytotoxicity analysis showed that the PU-HA films synthesized in this study were cytocompatible and could support human vein endothelial cells (HUVECs) adhesion and proliferation. 1. Introduction Thermoplastic polyurethanes (PU) have been widely used for various biomedical applications due to their excellent mechanical properties and proper blood compatibility. Recently, much effort has been focused on polyurethanes as blood-contacting materials, such as cardiovascular biomaterials, hemodialysis blood line sets, central venous catheters (CVC), and IV bags [1, 2]. However, surface-induced thrombosis, protein fouling, and cytocompatibility have become the major drawbacks that hinder their further biomedical applications as blood-contacting materials. Surface modification is an effective approach to improve the blood compatibility, the size, shape, and mechanical properties of the original material maintained. Many studies have been performed on producing a blood-compatible surface by tailoring with poly(ethylene glycol) (PEG) [3, 4], heparin [5, 6], heparin-like [7–9], phospholipid polymer [10–13], hirudin [14], sulfobetaine [15, 16], and so on. Although many hydrogels or hydrophilized surfaces exhibit good blood compatibility, most of these are not truly antithrombogenic but only antithromboadhesive [17] as they curtail or inhibit platelets and blood cell adhesion rather than prolong the coagulation time. Hyaluronan (HA), a linear biopolymer naturally abundant in mammalian tissues, is composed of repeating units of N-acetyl-D-glucosamine and D-glucuronic acid, linked by -(1,4) and -(1,3) glycosidic junctions [18]. HA has been identified as a nontoxic,
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