Fluoroalkylated antimicrobial peptides enables cytosolic delivery and eradication of intracellular Staphylococcus aureus

Intracellular bacteria survive are difficult to eradicate by conventional antibiotics. Antimicrobial peptides (AMPs) have garnered increasing attention due to their ability to exert broad-spectrum antibacterial effects through various mechanisms. However, they are also unable to effectively penetrate cell membranes to enter the cytoplasm. Fluorination has been proven to effectively enhance the ability of biopeptides to penetrate cell membranes. We designed a fluoroalkylated Omiganan (PFC-OMN) by conjugating a perfluorocarbon tag to a cysteine-terminated Omiganan (OMN) via a disulfide bond, enabling self-assembly into ~ 59 nm nanoparticles and glutathione-triggered release of active OMN in the cytosol. PFC-OMN retained extracellular activity against S. aureus (MIC = 12.5 µM) and exhibited markedly enhanced intracellular bactericidal potency (IMBC₉₉.₉ = 50 µM vs. > 800 µM for unmodified peptide). FITC-PFC-OMN showed 2.6-4.2× higher cellular uptake and broader cytosolic distribution compared with FITC-C-OMN. PFC-OMN displayed low hemolysis (HC₅₀ ≈ 325 µM) and macrophage cytotoxicity (IC₅₀ ≈ 450 µM). In a murine peritonitis model, PFC-OMN significantly reduced intracellular S. aureus counts. These results indicate that fluoroalkylation can enable AMP-mediated eradication of intracellular pathogens.