Biogenic Synthesis of Silver Nanoparticles for Colorimetric Detection of Fe3+ in Environmental Samples

New research from the University of Guilan in Rasht, Iran, has developed a cost-effective and environmentally friendly method for synthesizing silver nanoparticles (Ag NPs) using olive leaf extract. The Ag NPs have been found to have dual functionality as a colorimetric sensor for Fe3+ ions and an effective antimicrobial agent. This breakthrough has promising applications in environmental monitoring and biomedicine.

Key Takeaways:

• The biogenic synthesis of silver nanoparticles using olive leaf extract provides a green and cost-effective alternative to conventional chemical methods.
• The Ag NPs demonstrated dual functionality as a colorimetric sensor for Fe3+ ions, with a low detection limit of 0.81 mM and a limit of quantification of 2.7 mM.
• The sensor exhibited excellent selectivity for Fe3+ ions over competing metal ions and achieved recoveries of 86-92.5% in real water samples.
• The Ag NPs showed strong antibacterial activity against several species of bacteria, including B. subtilis, S. aureus, and E. coli.
• The cytotoxicity assays on Hu02 cells indicated low toxicity and effective cellular uptake, with intracellular imaging confirming Fe detection capability.
• Molecular docking simulations supported the antibacterial activity of the Ag NPs, showing binding free energies of -8.41 kcal/mol with S. aureus and -4.65 kcal/mol with E. coli proteins.
• The research concluded that this study presents a simple, cost-effective, and environmentally benign synthesis of OL-Ag NPs with dual functionality as a highly sensitive colorimetric sensor for Fe3+ and an effective antimicrobial agent.

Statistics:

• Detection limit: 0.81 mM
• Limit of quantification: 2.7 mM
• Recovery rates in water samples: 86-92.5%
• Antibacterial activity zone sizes: 1.6 mm (B. subtilis), 1.2 mm (S. aureus and E. coli), 1.0 mm (P. aeruginosa)
• Binding free energies: -8.41 kcal/mol (S. aureus), -4.65 kcal/mol (E. coli)

Sources:

• Biogenic synthesis of silver nanoparticles for colorimetric detection of Fe3+ in environmental samples: DFT calculations and molecular docking studies. Journal of Environmental Management, 2025;387:125880.
• University of Guilan Reports Findings in Nanoparticles (Biogenic synthesis of silver nanoparticles for colorimetric detection of Fe3+ in environmental samples: DFT calculations and molecular docking studies). Nanotechnology Weekly. June 9, 2025; p 2028.