Reprogrammed Implant Surface Enhances Neutrophil-Mediated Immunity for Accelerated Osseointegration

Implant-associated infections (IAI) pose a significant challenge to successful osseointegration. The initial immune response to IAI is dominated by neutrophils, whose function can be impaired by bacterial aggregation and hypoxic microenvironments. This study presents a novel approach to reprogram implant surfaces using phytic acid-Zn2+ coordinated nanopillars (PA-Zn@TiNPs) and oxygen self-supporting nanoparticles. This strategy effectively eradicates bacteria through the synergistic antibacterial adhesion of the superhydrophilic-like surface, the mechano-bactericidal effect of the nanopillars, and the chemo-biocidal effect of Zn2+, thereby inhibiting bacterial "head start." Simultaneously, continuous oxygenation fuels neutrophils with reactive oxygen species, enhancing intracellular sterilization. In vitro and in vivo experiments demonstrate that this reprogrammed interface accelerates neutrophil apoptosis and facilitates M2-macrophage polarization, ultimately promoting inflammation resolution and robust osseointegration. This innovative approach holds significant potential for preventing IAI and enhancing the long-term success of bone-implant integration.