Polyetheretherketone fibers woven fabrics coated nanostructured silicon nitride and load EGCG as artificial ligaments for promoting ligament-bone integration

Abstract

Design of an artificial ligament with osteogenic activity to promote ligament-bone integration for anterior cruciate ligament (ACL) reconstruction remains a huge challenge. In this work, polyetheretherketone fibers with nanostructured silicon nitride coating (PSN) and loading epigallocatechin gallate (EGCG) were woven into fabrics (PSN@EG) for artificial ligament application.The in vitro experiments confirmed that PSN@EG significantly upregulated M2 macrophage polarization that promoted secretory of anti-inflammatory cytokines while downregulated M1 macrophage polarization that inhibithed secretory of pro-inflammatory cytokines. Moreover, PSN@EG remarkably improved osteoblastic differentiation of rat bone marrow mesenchymal stem cells (BMSC) while suppressed osteoclastic differentiation of rat bone marrow-derived macrophages (BMM) in macrophage condition medium. The in vivo experiments revealed that PSN@EG promoted new bone formation for ligament-bone integration that inhibited fibrous encapsulation formation. It could be suggested that the synergistic effects of the optimized surface charactieristics (e.g., nano-micro topography), and sustained release of Si ions and EGCG caused the immunomodulatory of PSN@EG, which improved pro-osteogenic macrophage polarization that provided a favorable anti-inflammatory immune environment for enhancing osteogenesis while inhibiting osteoclastogenesis. In summary, PSN@EG with immunomodulatory significantly promoted osteoblastic differentiation while suppressed osteoclastic differentiation, thereby facilitating osteogenesis for ligament-bone integration. As a novel artificial ligament, PSN@EG has tremendous potential for ACL reconstruction.