A pH-responsive magnetic-controlled nanocomposite for precise and efficient vancomycin delivery in treating prosthetic joint infections

Prosthetic joint infection (PJI) presents a significant medical challenge, with current surgical and antibiotic strategies often limited by high recurrence rates, the need for multiple interventions, and rising antibiotic resistance. This study introduces vancomycin-loaded magnetic iron oxide nanoparticles (IONPs) incorporated into ZIF-8-based nanocomposites, termed Van-IONPs@ZIF-8, designed to deliver antibiotics directly to the PJI infection site under an external magnetic field (MF) for targeted antibacterial therapy. The Van-IONPs@ZIF-8 demonstrated excellent pH sensitivity, in vitro biocompatibility, and marked antibacterial efficacy against  Staphylococcus aureus . When subjected to an external MF, these magnetic nanocomposites effectively localized at infection sites. In vivo results indicated that the Van-IONPs@ZIF-8 + MF treatment significantly reduced bacterial loads on implants, decreased blood leukocyte counts, and mitigated inflammatory cell infiltration in surrounding tissues compared to controls. Concurrently, a marked reduction in both the number of pro-inflammatory cells and the levels of pro-inflammatory cytokines was observed, alongside a corresponding increase in inflammatory repair cells and reparative cytokines within the local tissues surrounding the infected implants. Thus, Van-IONPs@ZIF-8, in conjunction with an external MF, facilitates precise targeting of local infection sites and promotes rapid vancomycin release, representing a promising strategy for the safe and effective treatment of PJI.