A trilogy antimicrobial strategy for multiple infections of orthopedic implants throughout their life cycle

Bacteria-associated infection represents one of the major threats for orthopedic implants failure during their life cycles. However, ordinary antimicrobial treatments usually failed to combat multiple waves of infections during arthroplasty and prosthesis revisions etc. As these incidents could easily introduce new microbial pathogens in/onto the implants. Herein, we demonstrate that an antimicrobial trilogy strategy incorporating a sophisticated multilayered coating system leveraging multiple ion exchange mechanisms and fine nanotopography tuning, could effectively eradicate bacterial infection at various stages of implantation. Early stage bacteriostatic effect was realized via nano-topological structure of top mineral coating. Antibacterial effect at intermediate stage was mediated by sustained release of zinc ions from doped CaP coating. Strong antibacterial potency was validated at 4 weeks post implantation via an implanted model in vivo. Finally, the underlying zinc titanate fiber network enabled a long-term contact and release effect of residual zinc, which maintained a strong antibacterial ability against both Staphylococcus aureus and Escherichia coli even after the removal of top layer coating. Moreover, sustained release of Sr2+ and Zn2+ during CaP coating degradation substantially promoted implant osseointegration even under an infectious environment by showing more peri-implant new bone formation and substantially improved bone-implant bonding strength.