Surficial nano-deposition locoregionally yielding bactericidal super CAR-macrophages expedites periprosthetic osseointegration

Tracking and eradicating Staphylococcus aureus in the periprosthetic microenvironment are critical for preventing periprosthetic joint infection (PJI), yet effective strategies remain elusive. Here, we report an implant nanoparticle coating that locoregionally yields bactericidal super chimeric antigen receptor macrophages (CAR-MΦs) to prevent PJI. We demonstrate that the plasmid-laden nanoparticle from the coating can introduce S. aureus-targeted CAR genes and caspase-11 short hairpin RNA (CASP11 shRNA) into macrophage nuclei to generate super CAR-MΦs in mouse models. CASP11 shRNA allowed mitochondria to be recruited around phagosomes containing phagocytosed bacteria to deliver mitochondria-generated bactericidal reactive oxygen species. These super CAR-MΦs targeted and eradicated S. aureus and conferred robust bactericidal immunologic activity at the bone-implant interface. Furthermore, the coating biodegradability precisely matched the bone regeneration process, achieving satisfactory osteogenesis. Overall, our work establishes a locoregional treatment strategy for priming macrophage-specific bactericidal immunity with broad application in patients suffering from multidrug-resistant bacterial infection.