A Pure Zwitterionic PSBMA Coating With Ultra-Low Friction, Anti-Adhesion and High Stability for Blood-Contacting Catheters.

With the increasing demand for blood-contacting medical devices, surface-related limitations of conventional materials, including high friction, nonspecific adhesion, and insufficient long-term stability, have become critical challenges for clinical safety. To address these issues while retaining zwitterions' inherent advantages, this study proposes a "penetration-crosslinking-entanglement" strategy to fabricate an integrated pure poly sulfobetaine methacrylate (PSBMA) zwitterionic hydrogel coating on thermoplastic polyurethane (TPU). This process enables covalent bonding between PSBMA chains and the TPU matrix, together with extensive physical entanglement of long PSBMA chains, resulting in a robust coating-substrate integrated architecture. The positive and negative charge groups in PSBMA molecules strongly adsorb water molecules through electrostatic interactions, laying the foundation for the formation of a stable hydration layer. It renders the modified TPU surface superhydrophilic, with water contact angles below 20°, and significantly reduces the friction coefficient to below 0.03 while maintaining stable lubrication under various loads and shear rates. In addition, the coating effectively suppresses protein adsorption as well as blood cell adhesion and activation. Overall, this simple and scalable strategy achieves a synergistic enhancement of surface lubricity, anti-adhesion, stability, and blood compatibility of TPU, offering a promising solution for blood-contacting medical devices such as interventional catheters.