Synthesis of Silver Nanoparticles by Using Quercus Robur Knopper Gall Extracts.

Area of Science:

• Plant Biochemistry
• Nanotechnology
• Microbiology

Background:

• Insect galls, like Knopper galls from Cynipidae, are plant growths altering host tissue biochemistry.
• These galls can serve as a source for novel bioactive compounds.

Purpose of the Study:

• To explore the green synthesis of silver nanoparticles (AgNPs) using ethanolic extracts of *Quercus robur* Knopper galls.
• To characterize the synthesized AgNPs and evaluate their antimicrobial activity.

Main Methods:

• Green synthesis of AgNPs via reduction of silver nitrate (AgNO3) using gall extract.
• Characterization using UV-Vis spectrophotometry, ATR-FTIR, powder X-ray diffraction (PXRD), and transmission electron microscopy (TEM).
• Antimicrobial activity testing against *Bacillus subtilis*, *Staphylococcus aureus*, *Escherichia coli*, and *Pseudomonas aeruginosa*.

Main Results:

• UV-Vis spectroscopy confirmed AgNPs with a surface plasmon resonance peak at 418 nm.
• PXRD and TEM revealed well-dispersed, spherical AgNPs with a face-centered cubic structure and ~12 nm crystallite size.
• ATR-FTIR indicated polyphenolic and protein involvement in AgNP synthesis and stabilization.
• Synthesized AgNPs demonstrated strong inhibition against *B. subtilis* and *S. aureus*, and moderate inhibition against *E. coli* and *P. aeruginosa*.

Conclusions:

• *Quercus robur* Knopper gall extract is a viable and sustainable source for eco-friendly AgNP synthesis.
• The synthesized AgNPs possess significant antimicrobial properties, highlighting their potential therapeutic applications.
• This study showcases a novel application of plant galls in green nanotechnology.