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 the resulting hypoxic microenvironment pose significant challenges. These factors can impair neutrophil function, increasing the risk of IAI and implant failure. To address this, we've developed a novel approach: mechanochemically reprogramming the implant surface with phytic acid-Zn2+ coordinated nanopillars (PA-Zn@TiNPs) and oxygen self-supporting nanoparticles.

This innovative design leverages multiple mechanisms to combat infection and promote integration:

• Anti-bacterial adhesion: The superhydrophilic-like surface of the PA-Zn@TiNPs resists bacterial attachment.* Mechano-bactericidal effect: The nanopillars physically disrupt bacterial membranes, leading to their destruction.* Chemo-biocidal effect: Zn2+ ions released from the nanopillars exert a potent antimicrobial effect, further inhibiting bacterial growth and nascent biofilm formation.* Enhanced intracellular sterilization: Continuous oxygenation provided by the incorporated nanoparticles fuels neutrophils with reactive oxygen species (ROS), boosting their ability to kill bacteria.

Both in vitro and in vivo experiments have demonstrated the effectiveness of this strategy. It not only effectively eradicates bacteria and prevents biofilm formation but also accelerates neutrophil apoptosis and facilitates M2-macrophage polarization. These processes are crucial for promoting the resolution of inflammation and ultimately enhancing osseointegration.

This tailor-made, reprogrammed interface holds immense potential for improving implant outcomes. By empowering neutrophils to effectively combat infection and fostering a pro-healing environment, it paves the way for successful bone-implant integration and long-term implant success.