A Cecropin B-derived short peptide shows preliminary in vitro antibacterial and antibiofilm activity and modulates macrophage inflammatory gene expression

Background Peri-implantitis is a biofilm-associated inflammatory disease requiring effective, host-compatible antimicrobial strategies. Antimicrobial peptides offer potential antibacterial and host-modulatory benefits.Objective To evaluate the in vitro antibacterial, antibiofilm, cytocompatibility, hemocompatibility, HGF-related, and macrophage inflammatory effects of the Cecropin B-derived short peptide KN17-2.Methods Commercially synthesized KN17-2 was characterized by physicochemical prediction and Raman spectroscopy of the dried powder. Its antibacterial and antibiofilm activities against F. nucleatum, S. gordonii, and P. gingivalis were evaluated using MIC, MBC, biofilm, confocal microscopy, and SEM assays. Cytocompatibility and hemocompatibility were assessed using CCK-8, AO/EB fluorescence imaging, and erythrocyte hemolysis assays. HGF scratch-wound closure and selected inflammatory gene expression in RAW264.7 macrophages were also examined under basal and LPS-stimulated conditions.Results KN17-2 showed antibacterial activity against all three bacterial species, with MIC values of 62.5–75 μg/mL and MBC values of 200–250 μg/mL, and inhibited single-species biofilm formation. SEM observations suggested impaired bacterial membrane integrity after peptide treatment. In HGFs, the CCK-8 signal decreased at concentrations of 128 μg/mL and above, although CC50 was > 512 μg/mL. Hemolysis was negligible at 4–128 μg/mL, and HC50 was > 1024 μg/mL. HGF scratch-wound closure increased over time in both groups, but no significant between-group differences were observed at any individual time point. In RAW264.7 macrophages, KN17-2 induced gene- and time-dependent changes in selected inflammatory markers and partially attenuated LPS-induced TNF-α and iNOS expression.Conclusions KN17-2 showed preliminary in vitro antibacterial and antibiofilm activity, acceptable cytocompatibility and hemocompatibility, effects on HGF migration and adhesion but not scratch-wound closure, and partial modulation of macrophage inflammatory genes. Further studies involving peptide comparisons, multispecies biofilms, implant-related delivery and stability models, and in vivo validation are required before its therapeutic relevance to peri-implantitis can be established.