Functional and structural construction of photothermal-responsive PEEK composite implants to promote bone regeneration and bone-implant integration

Although poly (ether-ether-ketone) (PEEK) has been widely used in orthopedic surgeries, its clinical efficacy is challenged by ineffective bone regeneration and insufficient osteointegration. Herein, inspired by the Mortise-and-tenon joint in traditional Chinese architectural art, a novel strategy has been developed to construct photothermal-responsive PEEK composite implants, with tapered lock-groove edges as proof of concept, by incorporating graphene oxide (GO) loaded with polydopamine-coated nano-zirconia (PDA@ZrO₂) into PEEK (namely PGPZ composite). The PGPZ composite exhibits improved mechanical properties, good cytocompatibility and blood compatibility, excellent antibacterial ability and osteogenic activity remotely controlled by near-infrared irradiation (NIR). The cranial defects experiment on rabbits reveals that repeated NIR treatment on PGPZ composite implant significantly accelerates endogenous bone regeneration. More importantly, abundant newly-formed bone has materialized in the lock grooves, forming interlocked Mortise-and-tenon joints with the implant. This study not only pave the way for further clinical applications of the PEEK composite implants with improved bioactivities to promote bone regeneration and osteointegration, but also providing a novel strategy for structural and functional design of various tissue engineering implants.