Construction of nano-biomimetic coatings capable of catalyzing NO-generation based on the lysozyme phase transition reaction to improve the biocompatibility of polyurethane

As a versatile biomaterial, polyurethane (PU) finds extensive use in blood-contacting medical devices, including vascular grafts, central venous catheters, hemodialysis catheters, artificial heart valves, and blood oxygenators, etc. However, surface-induced thrombosis and difficulty in surface endothelialization after implantation are potential factors limiting their long-term use. In the present study, a lysozyme nanoparticle biomimetic coating (PTL) was first built on the PU surface based on the phase transition reaction of lysozyme. Subsequently, through sequential amidation reactions, heparin with anticoagulant performances and selenocystamine capable of catalyzing nitric oxide (NO) generation were immobilized onto the PTL surface, yielding a multifunctional nano-biomimetic coating with NO-generation and anticoagulant activities. The coating exhibited outstanding wettability, the ability to inhibit fibrinogen adsorption, and the capacity to catalyze NO generation from NO donors continuously. The as-prepared coating could reduce platelet adhesion, activation, and hemolysis, displaying superior anticoagulant performance. Meanwhile, the coating could promote endothelial cell (EC) proliferation and functional expression (vascular endothelial growth factor (VEGF) and NO) while significantly impeding smooth muscle cell (SMC) adhesion and proliferation, showing a good ability to facilitate endothelialization. Additionally, in the presence of NO donors, the coating could catalyze the NO liberation from donors continuously, further enhancing the blood compatibility and facilitating EC growth selectively. As a consequence, the strategy of this study can simultaneously impart PU with excellent hemocompatibility and rapid endothelialization, providing a new way for constructing anticoagulant and endothelium-promoting nano-biomimetic coatings on PU surfaces.