Synergistic coating of Laponite swollen-layer and heparin composite for enhanced antifouling and antithrombotic performance

When implantable medical devices come into contact with blood, acute thrombosis and inflammation often occur due to the adhesion and denaturation of plasma proteins, ultimately degrading device performance. To address this issue, we developed a gel-like coating with superhydrophilic properties, incorporating a heparin based outer layer designed to minimize foreign body reactions and enhance hemocompatibility. The coating was engineered using a layer-by-layer (LbL) assembly of poly-l-lysine (PLL), laponite (Lap), and heparin (Hep), utilizing electrostatic interactions. The successful formation of stable layers was confirmed by QCM-D analysis. The inner layer, composed of PLL/Lap multilayers, formed a gel-like structure that maintained superhydrophilicity and effectively prevented cell adhesion. The outermost PLL/Hep multilayers significantly suppressed thrombus formation by inhibiting plasma protein and red blood cell adsorption as well as platelet activation. The coating exhibited excellent stability, retaining its superhydrophilic properties and heparin functionality even after 7 days of immersion in DPBS. Additionally, in vitro hemocompatibility and cytocompatibility tests confirmed its non-toxicity and overall biocompatibility. These results highlight the potential application of this coating to various implantable medical devices, providing a robust solution for improving device performance and safety.