Toxicity of silver nanoparticles to a fish gill cell line: Role of medium composition

Abstract

In aqueous solutions, silver nanoparticle (AgNP) behavior is affected by a variety of factors which lead to altered AgNP size and toxicity. Our research aims to explore the effect of media composition on citrate-coated AgNP (cit-AgNP) behavior and toxicity to the cell line from rainbow trout (Oncorhynchus mykiss) gill, RTgill-W1. Three different exposure media (L15/ex, L15/ex w/o Cl and d-L15/ex) were used. These were characterized by varying ionic strength and chloride content, both of which had a dominant effect on the behaviour of cit-AgNP. Comparing the behaviour and toxicity of cit-AgNP in the different media, stronger agglomeration of cit-AgNP correlated with higher toxicity. Deposition of cit-AgNP on cells might explain the higher toxicity of agglomerated cit-AgNP compared to that of suspended cit-AgNP. The cit-AgNP concentration-response curves as a function of dissolved silver ions, and the limited prevention of toxicity by silver ligands, indicated that cit-AgNP elicited a particle-specific effect on the cells. Furthermore, the lysosomal membrane integrity was significantly more sensitive to cit-AgNP exposure than cellular metabolic activity or cell membrane integrity and showed the weakest protection by silver ligands. This revealed that cit-AgNP toxicity seems to particularly act on RTgill-W1 cell lysosomes. The newly developed low ionic strength medium, d-L15/ex, which can stabilize cit-AgNP and better mimic the freshwater environment, offers an excellent exposure solution to study cellular and molecular effects of NP to gill cells.

• Exposure medium
• lysosomal compartment
• nanoparticle agglomeration
• rainbow trout (Oncorhynchus mykiss)
• RTgill-W1 cells

Acknowledgements

We thank Christopher Buser (EMEZ-Electron Microscopy ETH Zürich, Zürich, Switzerland) for TEM analysis and David Kistler (Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, Dübendorf, Switzerland) for ICP-MS measurements.

Declaration of interest

The authors declared no personal interests related to this study. The authors alone are responsible for the content and writing of the paper. This work was supported by the Swiss National Science Foundation in the framework of the Swiss National Research Program 64 on the Opportunities and Risks of Nanomaterials.

Supplementary material available online

Supplementary Figures S1 and S2 and Tables S1 and S2