Green synthesis, characterization, and antibacterial activity of gold nanoparticles

H. H. Esmael; R. N. Taha; N. S. Mohamed

doi:10.15421/0226050

H. H. Esmael Al-Nahrain University
R. N. Taha Al-Nahrain University
N. S. Mohamed Al-Nahrain University

Keywords: green synthesis, gold nanoparticles, Syzygium aromaticum, antibacterial activity, MTT assay, LDH assay.

Abstract

Green synthesis of gold nanoparticles ( AuNPs ) offers an eco-friendly alternative to conventional chemical methods for bi o medical applications. In this study, AuNPs were synthesized using an aqueous extract of Syzygium aromaticum (clove), where phytochemicals acted as reducing and stabilizing agents. The synthesized nanoparticles were characterized using UV - v isible spectroscopy, X-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM). UV - v is analysis confirmed nanoparticle formation through a characteristic surface plasmon resonance band, while XRD revealed a face-centered cubic crystalline structure. AFM and TEM analyses showed predominantly spherical AuNPs with an average particle size of 15–20 nm. The antibacterial activity of clove-mediated AuNPs was evaluated against Staphylococcus aureus , Escherichia coli , and Pseudomonas aeruginosa using disc diffusion, MTT, and LDH assays. The results demonstrated a clear concentration-dependent antibacterial effect, with higher sensitivity observed for Gram-positive bacteria. Increased LDH release and reduced MTT activity indicated membrane damage and decreased bacterial viability, with promising applications.

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