Plasma treatment of biomedical polymers for immunomodulatory surfaces

The adverse macrophage-mediated immune response elicited by the surface of biomedical polymers is responsible for various complications observed during their clinical service, such as the intimal hyperplasia after replacements of prosthetic vascular grafts, and the aseptic loosening of implants used in dental and orthopedic fields. Therefore, endowing the surfaces of biomedical polymers with immunomodulatory ability is an appealing strategy to enhance their biological performances. Plasma immersion ion implantation (PIII) is a versatile and effective technique to modify the surface chemistry and topography, both of which can be tailored to modulate the inflammatory response elicited by implanted biomaterials. For example, after PIII treatment, the “marker of self” CD47 protein can be covalently immobilized on the surface of polytetrafluoroethylene (PTFE) to shield the implant from recognition by the host immune system. The well-adhered films with tunable nanoporous structures constructed on polyetheretherketone (PEEK) harmonize the early macrophage-mediated inflammatory response thus obtaining superior osseointegration. These surface modification strategies not only develop the knowledge about the regulation of the host immune response on biomaterials, but also provide new insights into the design of high-performance implants for biomedical applications.