Silver nanoparticles (AgNPs) are extensively employed for their antimicrobial and biomedical properties, yet concerns persist regarding their potential toxicity. While AgNPs can induce oxidative stress, membrane disruption, and DNA damage, in vivo data remain inconsistent. This study investigated whether batch-to-batch variability in nominally identical AgNPs of 10 nm size contributes to divergent in vivo toxicity outcomes. CD-1 (ICR) mice were intravenously injected with a single 10 mg/kg bw dose of spherical, citrate-coated 10 nm AgNPs from three different batches purchased from the same manufacturer. The mice were euthanized 24 h post-exposure for quantitative silver determination by inductively coupled plasma-mass spectrometry (ICP-MS) and histopathological evaluation of liver, spleen, lungs, kidneys, and brain. Autometallography and immunofluorescence were used to assess silver distribution and cellular localization in the hepatobiliary system. All the batches induced hepatobiliary toxicity, characterized by hepatocellular necrosis and gallbladder wall hemorrhage, of differing severity. The most toxic batches contained higher proportions of smaller AgNPs, suggesting that differences in size distribution influence toxicological outcomes. Silver agglomerates were localized within multiple cell types, indicating internalization and cell-specific cytotoxicity. These findings highlight that minor physicochemical variations affect in vivo results, underscoring the importance of nanoparticle characterization to improve reproducibility in nanotoxicological research.
Canesi et al. (Wed,) studied this question.