Form-Dependent Toxicity of Silver Nanomaterials in Rainbow Trout Gills

The toxicity of the form of nanoparticles is presently not well understood. The purpose of this study consists in comparing the toxicity of various forms of silver nanoparticles (nAg) in juvenile rainbow trout Oncorhynchus mykiss. Juveniles were exposed to various forms of polyvinyl-coated nAg of similar size for 96 h at 15 degrees C. After the exposure period, the gills were isolated and analyzed for Ag uptake/distribution, oxidative stress, glucose metabolism, and genotoxicity. Higher levels of Ag were detected in gills in fish exposed to dissolved Ag followed by spherical, cubic, and prismatic nAg. Size-exclusion chromatography of gill fractions revealed that the dissolution of nAg was observed for all forms of nAg where prismatic nAg released more important levels of Ag in the protein pool as in fish exposed to dissolved Ag as well. The aggregation of nAg was more important for cubic nAg in respect of the other forms of nAg. The data revealed that lipid peroxidation was closely associated with protein aggregation and viscosity. Biomarkers revealed changes in lipid/oxidative stress and genotoxicity, which were related to the loss of protein aggregation and inflammation (NO2 levels), respectively. In general, the observed effects were found for all forms of nAg where the effects from prismatic nAg were generally higher than for spherical and cubic nAg. The strong relationship between genotoxicity and inflammation response suggests the participation of the immune system in the observed responses of juvenile fish gills.

Automated summary

The toxicity of different forms of silver nanoparticles (nAg) in juvenile rainbow trout was compared in this study. It was found that dissolved Ag had the highest uptake and distribution in the fish gills, followed by spherical, cubic, and prismatic nAg. Dissolution of nAg was observed in all forms, with prismatic nAg releasing higher levels of Ag in the protein pool. Cubic nAg had a higher aggregation tendency compared to other forms. Lipid peroxidation was closely related to protein aggregation and viscosity. Biomarkers indicated changes in lipid/oxidative stress and genotoxicity, which were associated with protein aggregation loss and inflammation (NO2 levels), respectively. In general, the effects were observed in all forms of nAg, with prismatic nAg showing higher toxicity than spherical and cubic nAg. The strong relationship between genotoxicity and inflammation response suggests the involvement of the immune system in the observed responses of juvenile fish gills.