Mechanochemical Reprogramming of Implant Surfaces to Combat Infection and Promote Osseointegration

Implant-associated infection (IAI) is a serious complication that can lead to implant failure. The initial immune response to IAI is dominated by neutrophils, but their function can be impaired by bacterial aggregation and a hypoxic microenvironment. To address these challenges, we have developed a novel approach to mechanochemically reprogram implant surfaces using phytic acid-Zn2+ coordinated nanopillars (PA-Zn@TiNPs) and oxygen self-supporting nanoparticles.

The engineered PA-Zn@TiNPs surface offers a multi-pronged defense against IAI. The superhydrophilic-like surface prevents bacterial adhesion, the nanopillars provide a mechano-bactericidal effect, and Zn2+ ions exert a chemo-biocidal effect. This combination effectively eradicates bacteria and inhibits the establishment of infection. Additionally, the continuous oxygen supply fuels neutrophils with reactive oxygen species, enhancing their ability to kill bacteria.

In vitro and in vivo experiments have demonstrated the effectiveness of this strategy. The reprogrammed implant surface accelerates neutrophil apoptosis, a crucial step in resolving inflammation. It also promotes the polarization of macrophages towards the M2 phenotype, which is associated with tissue repair and regeneration. These changes ultimately lead to faster inflammation resolution and improved osseointegration.

This research highlights the potential of bioengineered implant surfaces to modulate the immune response and improve clinical outcomes. The development of advanced implant materials that can effectively combat infection and enhance long-term implant success holds great promise for the future of implantology.