The effects of silver nanomaterial shape and size on toxicity to Caenorhabditis elegans in soil media.

Silver nanomaterials (AgNMs) of various shapes and sizes are manufactured for different purposes and used as ingredients in a wide variety of products and applications. Recently, the toxicity of AgNMs has attracted significant attention. However, the effect of the shape of AgNMs (particles, wires, plates) on their toxicity in soil ecosystems remains poorly understood. In this study, we added AgNMs of different shapes and sizes (silver nanoparticles, AgNPs; 10 μm silver nanowires, 10-AgNWs; 20 μm silver nanowires, 20-AgNWs; silver nanoplates, AgPLs) to natural soil and determined their effect on the growth and reproduction of the free-living nematode, Caenorhabditis elegans. AgNPs and AgPLs were found to inhibit the growth and reproduction of C. elegans, whereas AgNWs had a negligible effect. Among these AgNMs, the results of this study suggest AgNPs are the most toxic. This confirms that the shape of AgNPs plays a significant role in their toxicity level. To the best of our knowledge, this is the first comparative analysis of the shape-dependent toxicity of AgNMs in the soil using nematode C. elegans. This study provides a scientific reference for assessing shape-dependent soil nanotoxicity.