Fabrication of an Antibacterial/Anticoagulant Dual-Functional Surface for Left Ventricular Assist Devices via Mussel-Inspired Polydopamine Chemistry

Infections and thrombosis remain unsolved problems for implanted cardiovascular devices, such as left ventricular assist devices. Hence, the development of surfaces with improved blood compatibility and antimicrobial properties is imperative to reduce complications after artificial heart implantation. In this work, we report a novel approach to fabricate multifunctional surfaces for left ventricular transplanted ventricular assist devices (LVADs) by immobilizing nitric oxide (NO) generation catalysts and heparin and reducing silver nanoparticles in situ. The general view, structure, and chemical compositions of the pure/modified surfaces were characterized using digital imaging, scanning electron microscope (SEM), atomic force microscope (AFM), water contact angle (WCA), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma (ICP). All of the results demonstrated that the AgNPs and heparin were successfully immobilized on the surface. The Cu ions and NO release experimental results showed that the immobilized copper ions could catalyze the production of NO from S-nitrosothiols within the biological system. Meanwhile, due to the synergistic anticoagulant effect of NO and surface-immobilized heparin, the fabricated modified surfaces exhibited antiplatelet adhesion activities and good hemocompatibility. Finally, the antimicrobial activity of the samples was evaluated by Escherichia coli and Staphylococcus aureus, and cytocompatibility was measured using human umbilical vein endothelial cells (HUVECs). The results demonstrated that silver nanoparticles (AgNPs) immobilized by surface reduction reaction did not cause any significant inhibition of cell proliferation while providing stable and effective antimicrobial properties. We envision that this simple surface modification strategy with bifunctional activities of antimicrobial and anticoagulant will find widespread use in clinically used indwelling left ventricular assist devices.