DESIGN AND CHARACTERIZATION OF AMP-COATED SILVER CORE–SHELL NANOPARTICLES TARGETED ANTIBACTERIAL THERAPY

Abstract

The rise of multidrug-resistant (MDR) pathogens necessitates innovative antimicrobial strategies beyond conventional antibiotics. This study focuses on designing and characterizing antimicrobial peptide (AMP)-coated silver core-shell nanoparticles (AgNPs) as a targeted antibacterial therapy. Silver nanoparticles were synthesized via chemical reduction and green methods, then functionalized with AMPs to combine the broad-spectrum antimicrobial activity of AgNPs with the specificity and membrane-disrupting properties of AMPs. The nanoparticles were extensively characterized using UV-Visible spectroscopy, which confirmed surface plasmon resonance peaks at 400-430 nm, with a red shift indicating successful AMP coating. Fourier-transform infrared spectroscopy (FTIR) revealed characteristic biomolecular interactions stabilizing the nanoparticles, while dynamic light scattering (DLS) showed particle sizes ranging 7-12 nm with moderate polydispersity. X-ray diffraction (XRD) confirmed face-centered cubic crystalline structure of the silver cores. Antimicrobial assays demonstrated potent, dose-dependent activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria, with minimum inhibitory concentrations (MIC) as low as 1 μg/mL for some strains. The AMP coating enhanced nanoparticle stability while reducing silver cytotoxicity. Synergistic effects between the silver core and peptide shell resulted in improved bactericidal activity compared to either component alone, particularly against MDR strains. These findings highlight the potential of AMP-coated AgNPs as a promising alternative to conventional antibiotics, offering targeted antimicrobial action with reduced toxicity concerns. Further optimization of peptide conjugation and in vivo studies are warranted to advance this technology toward clinical applications.