Characterization and antibacterial effect of green-synthesised silver nanoparticles using different extraction
Wael Dagher1, Abeer Alassod1, Mhd Firas Al Hinnawi2
1Textile Industries Mechanical Engineering and Techniques Department, Faculty of Mechanical and Electrical Engineering, Damascus University Damascus Syria abeeralassod@outlook.com.
Abstract:
The study investigates the effective green biosynthesis of silver nanoparticles (AgNPs) from silver nitrate (AgNO3) as a precursor using Syrian Sidr leaf extract as a reducing and stabilizing agent. Three extraction methods (Maceration, ultrasound-assisted, and Soxhlet) were tested using six solvents. The Soxhlet method with a methanol/water mixture (60 : 40) provided the highest phenolic (192.83 ± 0.3 mg g-1) and flavonoid (59.48 ± 7.45 mg g-1) yields and was selected for nanoparticle biosynthesis. Further characterization confirmed the synthesis using these analytical techniques. UV-Vis spectroscopy revealed the formation of ZL-AgNPs via a characteristic plasmon resonance peak at 430 nm; FTIR indicated surface functional groups from the plant extract; XRD confirmed a cubic crystalline structure with an average crystallite size of 11 nm; SEM images showed spherical particles below 20 nm; EDX analysis depicted a dominant silver signal (85 wt%) with minor contributions from organic compounds. The biosynthesised ZL-AgNPs exhibited significant antibacterial activity against Gram-positive bacterium Staphylococcus aureus and the Gram-negative bacterium Escherichia coli, with inhibition zones ranging from 13.76 ± 0.25 to 21.65 ± 0.34 mm for E. coli and 0 to 16.73 ± 0.21 mm for S. aureus at concentrations of 25-200 μg mL-1. The positive control (Gentamicin, 200 μg mL-1) showed the largest inhibition zones, while the plant extract control demonstrated moderate activity at higher concentrations. These findings confirm the distinctive physicochemical properties and strong antibacterial potential of ZL-AgNPs for prospective biomedical applications.
