Fusion Peptide-Engineered Polyetheretherketone Implants with Photo-Assisted Anti-Pathogen and Enhanced Angiogenesis for in vivo Osseointegrative Fixation

Owing to its superior mechanical and physicochemical characteristics, polyetheretherketone (PEEK) is considered a potent orthopedic material. Yet, poor bactericidal, osseointegrative and angiogenic properties of bioinert PEEK collectively hamper its clinical adoption. Herein, we present a strategy for developing multifunctional hierarchical coatings bearing a synthetic fusion peptide and polydopamine/silver nanoparticles (pDA/AgNPs) bio-heterojunctions (bio-HJs), in an attempt to empower PEEK with triple-modal abilities, which prevents bacterial infection, enhances ossification and promotes re-vascularization for physiological osseointegrative fixation. By harnessing the adhesion of bioinspired pDA, AgNPs are facilely immobilized onto peripheral surface and incorporated into interior cavity of micro/nano-porous sulfonated PEEK (SP) to form hierarchical pDA/AgNPs heterostructures. The bio-HJs coatings exhibit robust and repeatable bacteria-eradicating ability, assisted by near-infrared illumination, due to the synergistic effects of the metal ion/photothermal therapy. The fusion peptide-engineered PEEK exhibits osteogenesis activity in terms of promoting osteoblast proliferation, spreading, boosting the synthesis and secretion of osteogenesis-related genes. Besides, the fusion peptide-engineered PEEK also has the ability to promote HUVECs growth, reproduction, and tube formation, facilitating the synthesis and secretion of angiogenesis-associated genes. Moreover, the results of the in vivo experiments further corroborate the in vivo osteointegration and angiogenic abilities of materials. Expectantly, the multifunctional coatings with the presented triple-therapeutic effects represent a prospective clinical solution to address the current clinical challenges associated with the use of PEEK implants.