Biosynthesis of Silver Nanoparticles using Carya Illinoinensis Extract for Antibacterial Applications

Abstract

This study presents an eco-friendly approach for synthesizing silver nanoparticles (AgNPs) using Carya illinoinensis (pecan nut) leaves extract as a natural reducing and stabilizing agent. Extracts prepared at different reaction times were examined for protein, sugar content, and antioxidant activity. The 4-hour extract demonstrated the highest antioxidant capacity, indicating a greater concentration of reducing biomolecules suitable for nanoparticle formation. AgNPs synthesized using this extract and varying AgNO₃ concentrations produced a distinct color change, confirmed by UV–visible spectroscopy with a characteristic SPR peak at 398 nm. SEM and TEM analyses revealed predominantly spherical nanoparticles with sizes ranging from 2 to 60 nm, while EDX confirmed elemental silver as the primary constituent. FT-IR spectra indicated the presence of phenolic, polyphenolic, and protein-based functional groups on the nanoparticle surface, contributing to stabilization. Antibacterial assays showed strong inhibition zones against Pseudomonas aeruginosa (17 ± 0.50 mm), Klebsiella pneumoniae (14 ± 0.10 mm), E. coli, Bacillus subtilis, and Staphylococcus aureus, with activity increasing proportionally to nanoparticle concentration. The findings demonstrate that pecan leaves extract is a viable, low-cost, and sustainable source for producing bioactive AgNPs with significant antimicrobial potential.

Keywords: Green Synthesis, Silver Nanoparticles, Carya Illinoinensis, Antioxidant Capacity, Antimicrobial Activity.