Macrophage-membrane-camouflaged lipid-polymer hybrid nanoparticles for target-specific biofilm penetration and eradication of methicillin-resistant staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) biofilms present a formidable therapeutic challenge due to the dense extracellular polymeric substance (EPS) matrix that restricts antibiotic penetration. Here, we engineered biomimetic macrophage-membrane-camouflaged lipid-polymer hybrid nanoparticles (M-LPHNs) designed for targeted delivery and enhanced eradication of MRSA biofilms. M-LPHNs were prepared via emulsification-sonication followed by extrusion-mediated cell membrane coating, yielding monodisperse core-shell spherical structures (∼150 nm, PDI < 0.20) with high colloidal stability in serum. The biomimetic coating imparted a negative surface potential (-28 mV) matching native macrophage membranes and sustained high drug encapsulation efficiencies for vancomycin (78.6%) and daptomycin (84.2%). In vitro susceptibility microdilution assays demonstrated a 4-fold reduction in minimum inhibitory concentration (MIC90) for M-LPHNs compared to free antibiotics. Time-kill kinetics revealed rapid bactericidal activity, achieving >3-log10 kill within 4 h and complete clearance (<10 CFU/mL) at 12 h without secondary regrowth. Scanning and transmission electron microscopy, alongside Live/Dead CLSM assays, confirmed that M-LPHNs induce localized plasma membrane disruption, wall thinning, and intracellular leakage. Quantitative flow cytometry confirmed 92.4% calcein leakage, while in silico molecular dynamics simulations demonstrated lipid acyl chain disordering and membrane nanopore formation. Cytotoxicity assays confirmed high biocompatibility in Caco-2 cells (>92% viability) and negligible hemolysis (<1.8%). M-LPHNs represent a promising biomimetic nanomedicine platform for overcoming matrix barriers in recalcitrant MRSA biofilm infections.