Interlayer-reinforced semi-IPN hydrogel coatings for durable lubrication and rivaroxaban-assisted antithrombotic activity on thermoplastic polyurethane

Thermoplastic polyurethane (TPU) is widely used in interventional medical devices because of its favorable mechanical properties and processability, but its inherent hydrophobicity and poor lubricity can promote tissue friction and thrombogenic responses during blood contact. Here, we developed an interlayer-reinforced semi-interpenetrating polymer network (semi-IPN) hydrogel coating for simultaneous lubrication and rivaroxaban-assisted antithrombotic modification of TPU. Polyvinylpyrrolidone (PVP) was physically interpenetrated within a crosslinked hydroxyethyl methacrylate/polyethylene glycol diacrylate (HEMA/PEGDA) network, while a polyurethane acrylate (PUA) interlayer was introduced to enhance coating-substrate interfacial stability. The optimized coating reduced the water contact angle of TPU from 91.10 ° to approximately 18.75 ° and decreased the coefficient of friction from 0.612 to 0.006, while maintaining stable lubrication over 50 friction cycles. Rivaroxaban was physically incorporated into the semi-IPN coating, and quantitative release measurements showed strong short-term drug retention, with only 0.413 ± 0.042% cumulative release in PBS after 24 h. The rivaroxaban-containing coating significantly prolonged activated partial thromboplastin time (APTT) to 67.33 ± 2.52 s, compared with 39.67 ± 1.53 s for the drug-free lubricious coating and 24.67 ± 1.15 s for unmodified TPU. Consistently, reduced platelet adhesion and thrombus formation were observed under static in vitro blood-contact conditions. Cytocompatibility evaluation further showed that the selected PUA-based coating maintained high cell viability, whereas PEI-based interlayers exhibited comparatively lower, although still acceptable, viability. These results demonstrate a robust interfacial strategy for constructing highly lubricious TPU surfaces with rivaroxaban-assisted antithrombotic functionality, while further long-term release, dynamic blood-contact, and in vivo evaluations remain necessary for translational assessment.