Copper ferrite heterojunction coatings empower polyetheretherketone implant with multi-modal bactericidal functions and boosted osteogenicity through synergistic photo/Fenton-therapy

Drug-free antibacterial therapy, such as photodynamic therapy and chemodynamic therapy, has become a mainstream in the treatment of implant-associated infection (IAI) due to its considerable potential on effective eradication of pathogenic bacteria via yielding overwhelming reactive oxygen species (ROS). However, superfluous ROS after therapeutical process may elicit a detrimental effect on subsequent tissue regeneration. To address this tough issue, we innovatively devise a photo-activated copper ferrite (CuFe2O4) heterojunction coating on bioinert polyetheretherketone (PEEK) implant through hydrothermal treatment and π-π-π stacking. The heterojunction coatings not only generate localized hyperthermia and ROS upon 808 nm NIR illumination, but also trigger Fenton(-like) reaction and glutathione (GSH) depletion in bacterial infectious microenvironment (IME), all leading to robust and cyclic antibacterial property through synergistic photothermal/photodynamic/chemodynamic therapy. Besides, the decorated implants are demonstrated to show superior cytocompatibility and osteogenic-promoting capability. The mice subcutaneous implantation further confirms the excellent in vivo photo-disinfection. The advantage of the heterojunction coatings lies on its enhancement in tissue generation and osteogenesis after antibacterial dynamic therapy because the liberation of micronutrient element (Cu, Fe) is significantly augmented exposed to NIR light, showing photo-enhanced osteogenicity. As envisaged, this work provides a new strategy to empower PEEK implants with an integrative feature of bacteriostasis and osteogenicity to combat intractable IAI through synergistic photo/Fenton-therapy.