Neutrophil membrane-coated nanoparticles exhibit increased antimicrobial activities in an anti-microbial resistant K. pneumonia infection model

To investigate the efficacy and safety of neutrophil membrane-coated nanoparticles mediated KLA peptides (KLAKLAKKLAKLAK) and gentamicin in the targeted therapy of anti-microbial resistant Klebsiella pneumoniae (K. pneumonia) lung infection.The characteristics of KLA-neutrophils nanoparticles (NNPs) are identified via dynamic light scattering (DLS), transmission electron microscope (TEM), SDS-PAGE, Western blot, quantitative flow cytometry (QFCM) and confocal microscopy. The safety of KLA-NNPs both in vitro and in vivo is evaluated by hemolysis test, platelet α granule membrane protein concentration, protein adsorption capacity, in vitro macrophage phagocytosis, weight change, liver function indicators, blood biochemical indicators, and pathological changes of vital organs in mice. The efficacy of KLA-NNPs is determined by time-kill assay, fluorescent label test, intracellular bacterial content, caspase-1 activity, survival rate, and HE staining both in vitro and in vivo.The prepared KLA-NNPs have a typical "core-shell" structure, uniform nanometer size, and retain the membrane proteins on the neutrophil membrane that achieve functional effects. In vitro safety analysis showed that KLA-NNPs have good blood compatibility and can inhibit macrophage phagocytosis in vitro. KLA-NNPs can effectively release KLA and significantly reduce intracellular bacteria and caspase-1 activity. In vivo safety analysis and efficacy analysis revealed that KLA-NNPs have good biocompatibility and could effectively improve the survival rate of mice.The prepared KLA-NNPs have good nano-medicine chemical and physical properties and safety. It can evade immune system clearance, achieve high-efficiency targeted aggregation and drug delivery to bacterial infection sites, and effectively inhibit the development of pneumonia induced by drug-resistant K. pneumonia.