GREEN-SYNTHESISED SILVER NANOPARTICLES CONJUGATED WITH Bac8cGC PEPTIDE: AN INNOVATIVE PLATFORM TO COMBAT BACTERIAL INFECTIONS

Nanotechnology offers vast opportunities across biomedical, pharmaceutical, and environmental fields, with silver nanoparticles (AgNPs) emerging as one of its most promising tools due to their potent antibacterial properties. Their effectiveness is particularly enhanced when combined with antimicrobial peptides, providing potential alternatives to conventional antibiotics in the fight against resistant pathogens. In this study, AgNPs were synthesized using a green method based on ethanolic ginger extract, highlighting the environmental sustainability of the process. The nanoparticles were subsequently conjugated with the antimicrobial peptide Bac8cGC, synthesized through solid-phase peptide synthesis and terminally modified with a cysteine residue to enable direct conjugation via free thiol residue. The synthesized AgNPs were extensively characterized using multiple analytical techniques, including UV-Vis spectroscopy, differential centrifugal sedimentation (DCS), dynamic light scattering (DLS), zeta potential measurements, and transmission electron microscopy (TEM). Results confirmed successful nanoparticle formation with good colloidal stability (PdI 0.2, zeta potential −28 mV), a clear plasmon resonance peak at 430–450 nm, and spherical morphology with an average diameter of 20 nm. The peptide was verified by mass spectrometry, although purification was not achieved. Bioconjugation of AgNPs with Bac8cGC was validated using DLS, DCS, UV-Vis and FTIR analyses. FTIR confirmed the interaction between peptide functional groups and nanoparticle surfaces, though evidence of partial aggregation and incomplete conjugation pointed to the need for improved experimental protocols. Antimicrobial assays against Staphylococcus aureus revealed strong activity from the pure peptide and enhanced performance from the AgNPs/@Bac8cGC conjugate, suggesting a synergistic effect. Nevertheless, optimization of peptide purification and conjugation methods remains essential. Finally, collagen-chitosan scaffolds functionalized with the peptide and the conjugate were developed and tested. Live-dead assays and confocal microscopy demonstrated promising antibacterial effects, supporting their potential use in biomedical applications. In conclusion, this work establishes a solid foundation for further research on peptide-functionalized silver nanoparticles, advancing innovative antimicrobial strategies based on sustainable nanomaterial peptide systems.