The high aspect ratio of silver nanowires is expected to alter their transport and toxicity relative to spherical silver nanoparticles in natural environments and organisms. The University of Florida collaboration aims to identify specific characteristics of silver nanowires that influence their toxicity in aquatic cellular and organismal models. To accomplish this, the toxicity of silver nanowires that differ in length and diameter will be evaluated in rainbow trout gill and gut cells lines, embryos, and larvae using a wide variety of high content screening toxicity assays. Cytotoxicity endpoints include changes in lysosomal acidity and size, increases or decreases to the mitochondrial membrane potential, impacts of silver nanowire exposure to membrane integrity, and measurements of ATP production to assess general cytotoxicity. In addition, changes to cellular bioenergenetics and metabolism will be investigated. Whole organism toxicity endpoints include acute and chronic toxicity, bioaccumulation and tissue distribution, and trophic transfer of silver nanowires from Daphnia to rainbow trout larvae. The mechanism of toxicity will also be explored using RNA seq to evaluate the transcriptomic response of fish to silver nanowires. The primary objective of this project is to identify characteristics of silver nanowires that influence their toxicity to ecosystems and organisms, and then use this information to guide the development of silver nanowires toward safer options.