Ag Ions Versus Ag Nanoparticle-Embedded Glass for Antimicrobial Activity Under Light

Incorporating silver nanoparticles (NPs) into a host material has been recognized to limit the release of Ag+ ions, yet their efficacy in neutralizing nearby microorganisms remains uncertain. This study aims to compare the toxicity of Ag+ ions versus the plasmonic effect of Ag NPs within a glass matrix, assessing their respective killing efficiency and mechanisms against microorganisms. To achieve this objective, a simple ion exchange technique was employed to embed glass with silver ions, nanoclusters (NCs), or NPs, which was confirmed by UV–Vis-NIR spectrometer, photoluminescence (PL), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The biocidal action of these Ag species on model Escherichia coli (E. coli) bacteria was investigated in the absence and presence of visible light. The findings revealed that in the absence of light, plasmonic Ag NPs were less toxic to E. coli compared to Ag+ ions due to the predominant release of Ag+ ions dictating the antibacterial effect. However, exposure to visible light triggered the plasmonic effect in Ag NPs to disintegrate 100