3D Printed Bioactive Mechanical-Adaptive Polyetheretherketone Implants with Non-Invasive Tracking for Immunomodulatory Osseointegration

Polyether-ether-ketone (PEEK) has become a much-attracted biomedical implant material in orthopedic surgery, serving as a more biocompatible alternative to conventional metals. However, the inherent bioinert and mismatched mechanical surface of PEEK have limited their optimized bone fixation and repair. In this work, a PEEK implant is printed and a bioactive mechanical-adaptive surface via in situ chemical linking of photoluminescent elastomeric poly(citrate-silicon) (PCS) polymer (PEEK-PCS) is subsequently constructed, which could be used for real-time bioimaging and enhanced osseointegration. The PEEK-PCS surface exhibits viscoelastic properties, enabling it to conform to complex tissue geometries and effectively alleviate surface stress. Furthermore, PEEK-PCS modulates the inflammatory response by promoting macrophage M2 phenotypic polarization and reducing the expression of inflammatory factors. Additionally, PEEK-PCS promotes the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), significantly enhancing the osseointegration and osteogenesis ability of PEEK implants. Notably, PEEK-PCS demonstrates excellent autofluorescence properties both in vitro and in vivo, along with remarkable fluorescence stability over 14 d in vivo, suggesting real-time tracking potential of bioimaging. Compared to traditional coated implants, PEEK-PCS provides distinct advantages in surface adhesion, mechanical compatibility, real-time bioimaging, and osseointegration, representing a promising solution for implant-related bone repair.