Synergies of the submicron/microporous structures and gallium phytate coating on a polyetherketoneketone composite for facilitating synostosis and resisting infection.

Implant-related infections caused by invasion of bacteria is one of the most common complications during orthopedic interventions, and rapid synostosis is beneficial for stabilizing the implants and resisting infection. Herein, a niobium oxide/polyetherketoneketone composite (NP) was prepared, and submicron/microporous structures were created on NP (forming NPsm) using a picosecond laser. Subsequently, a gallium phytate (GP) coating was deposited on NPsm (forming NPsmG) through phytic acid chelation with gallium ions. The results demonstrated that NPsmG, with improved surface performances, remarkably facilitates the adhesion, migration, proliferation and differentiation of osteoblasts in vitro. Moreover, NPsmG, through its anti-inflammatory effects, promotes M2 macrophage polarization and the secretion of anti-inflammatory factors, thereby establishing a favorable microenvironment for osteogenic differentiation and synostosis. The significant improvements in the cellular responses of osteoblasts and macrophages are attributed to the synergistic effects of the bioactive niobium oxide, submicron/microporous structures and GP coating. NPsmG exhibited good antibacterial performance in vitro and efficiently resisted infection in vivo owing to the sustained release of Ga3+ ions. The in vivo experiments further demonstrated that NPsmG remarkably promotes bone regeneration and synostosis. Overall, the integration of a hierarchically structured surface and a GP coating on NPsmG provides a novel strategy for simultaneously promoting osteogenesis and preventing infection, highlighting its potential as a promising orthopedic implant material.