Metal element-fusion peptide heterostructured nanocoatings endow polyetheretherketone implants with robust anti-bacterial activities and in vivo osseointegration

Abstract

Polyetheretherketone (PEEK), renowned for its exceptional mechanical properties and bio-stability, is considered a promising alternative to traditional metal-based implants. However, the inferior bactericidal activity and the limited angiogenic and osteogenic properties of PEEK remain the three major obstacles to osseointegration in vivo. To overcome these obstacles, in this work, a versatile heterostructured nanocoating was conceived and equipped on PEEK. This nanocoating was designed to endow PEEK with the ability of photo-activated pathogen disinfection, along with enhanced angiogenesis and osteogenesis, effectively addressing the triple-barrier challenge towards osseointegration. The crafted nanocoating, encompassing diverse nutritional metal elements (Fe³⁺, Mg²⁺, and Sr²⁺) and a fusion peptide adept at promoting angiogenesis and osteogenesis, was seamlessly decorated onto PEEK. The engineered implant exhibited an antibacterial activity of over 94% upon near-infrared illumination by virtue of the photothermal conversion of the polyphenol nanocoating. Simultaneously, the decorated hierarchical nanocoatings synergistically promoted cellular adhesion and proliferation and up-regulated angiogenesis-/osteogenesis-associated cytokine expression in endothelial/osteoblast cells, resulting in superior angiogenic differentiation and osteoinductive capability in vitro. Moreover, an in vivo assay in a rabbit femoral defect model revealed that the decorated implant can achieve ameliorative osseointegrative fixation. Collectively, this work offers a practical and instructive clinical strategy to address the triple-barrier challenge associated with PEEK-based implants.