Thus, the release rate and bioavailability of silver ions is
crucial for the toxicity of nano-Ag. Studies have suggested
that physicochemical properties of nano-Ag play an important
role in its antimicrobial activity. However, the influence
of the size, shape, coating, and crystallographic facet appears
to be mainly related to different release kinetics of silver ions.
The presence of common ligands reduces the bioavailability of
silver ions and mitigates its toxicity (Xiu et al., 2011). A recent
study found that low concentration (sublethal) of silver ions or
nano-Ag enhances E. coli growth, suggesting a hormetic
response that could be counterproductive to its antimicrobial
applications