Reprogrammed Implant Surface Combats Infection and Promotes Osseointegration

The onset of implant-associated infection (IAI) triggers a cascade of immune responses, initially dominated by neutrophils. However, bacterial aggregate formation and a hypoxic microenvironment pose significant challenges, impairing neutrophil function and increasing the risk of IAI and implant failure. To address these challenges, we mechanistically reprogrammed the implant surface using phytic acid-Zn2+ coordinated nanopillars (PA-Zn@TiNPs) and oxygen self-supporting nanoparticles. This innovative design integrates three key functionalities: a superhydrophilic-like surface for anti-bacterial adhesion, nanopillars for mechano-bactericidal effects, and Zn2+ for chemo-biocidal effects. This combined approach effectively eradicates bacteria and inhibits biofilm formation. Additionally, continuous oxygenation provided by the nanoparticles enhances intracellular sterilization by neutrophils through increased reactive oxygen species production. Both in vitro and in vivo experiments demonstrated that this strategy accelerates neutrophil apoptosis and facilitates M2-macrophage polarization, ultimately promoting inflammation resolution and osseointegration. This tailor-made reprogrammed interface unlocks the potential of neutrophils to prevent IAI and significantly enhance bone-implant integration.