Antibacterial activity of silver nanoparticle LED-synthesized using Citrus maxima peels

Abstract

Silver nanoparticles have garnered significant attention in research and applications due to their unique properties. The synthesis of these nanoparticles has aligned with the principles of green chemistry, utilizing environmentally-friendly materials and techniques. In this study, silver nanoparticles were synthesized using the Citrus maxima peel extract and blue LED irradiation. The pectin, flavonoids, and phenolic acids in the C. maxima extract acted as effective reductants and primary stabilizers for nanoparticle formation. The influence of different light-emitting diodes and irradiation time on nanoparticle synthesis was investigated. Ideal conditions for silver nanoparticle formation were observed with the assistance of blue LED irradiation for 120 min. Characterization techniques such as transmission electron microscopy, X-ray diffraction analysis, ultraviolet-visible spectroscopy, and Fourier-transform infrared spectroscopy confirmed the successful synthesis of spherical nanoparticles with an average size of 12.2 nm. The antibacterial activity of the silver nanoparticles was evaluated against four bacterial strains: Lactobacillus fermentum, Pseudomonas aeruginosa, Staphylococcus aureus, and Salmonella enterica. The nanoparticles exhibited stronger inhibitory effects against gram-negative compared to gram-positive bacteria, with half-maximal inhibitory concentrations of 9.4, 18.1, 73.3, and 88.5 pM for P. aeruginosa, L. fermentum, S. aureus, and S. enterica, respectively. These findings highlight the potential of bio-synthesized nanoparticles with small size and high antibacterial activity.

Keywords

• antibacterial activity
• citrus maxima
• led irradiation
• silver nanoparticles