Green Synthesis of Ginger-Extract-Mediated Silver Nanoparticles for Antibacterial Activity and Selective Colorimetric Detection of Mercury Ions

Abstract

This study reports the eco-friendly synthesis of silver nanoparticles (AgNPs) using ginger (Zingiber officinale) extract as a natural reducing and capping agent. The ginger-extract-mediated AgNPs (GE-AgNPs) were spherical, stable, and exhibited a characteristic surface plasmon resonance peak at 457 nm. The nanoparticles demonstrated excellent dual functionality. First, they served as a selective and sensitive colorimetric sensor for toxic mercury (Hg2+) ions in water, showing a visible color change from brown to colorless, a linear detection range of 10–180 nM, and a low detection limit of 92.7 nM. The sensor performed reliably in real water samples with minimal interference from other common ions. Second, the GE-AgNPs displayed enhanced antibacterial activity against both Gram-positive and Gram-negative bacterial strains, outperforming pure ginger extract. This work highlights GE-AgNPs as a sustainable, multifunctional nanomaterial for rapid on-site mercury monitoring and antimicrobial applications.