Article pubs.acs.org/est
Toxicogenomic Responses of Nanotoxicity in Daphnia magna Exposed to Silver Nitrate and Coated Silver Nanoparticles Helen C. Poynton,*,† James M. Lazorchak,‡ Christopher A. Impellitteri,‡ Bonnie J. Blalock,† Kim Rogers,§ H. Joel Allen,‡ Alexandre Loguinov,∥ J. Lee Heckman,⊥ and Shekar Govindasmawy⊥ †
University of Massachusetts, Boston, Boston MA, United States U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, United States § U.S. Environmental Protection Agency, Office of Research and Development, Las Vegas, NV, United States ∥ University of California, Berkeley, Berkeley, CA, United States ⊥ Shaw Environmental and Infrastructure, Cincinnati, OH, United States ‡
S Supporting Information *
ABSTRACT: Applications for silver nanomaterials in consumer products are rapidly expanding, creating an urgent need for toxicological examination of the exposure potential and ecological effects of silver nanoparticles (AgNPs). The integration of genomic techniques into environmental toxicology has presented new avenues to develop exposure biomarkers and investigate the mode of toxicity of novel chemicals. In the present study we used a 15k oligonucleotide microarray for Daphnia magna, a freshwater crustacean and common indicator species for toxicity, to differentiate between particle specific and ionic silver toxicity and to develop exposure biomarkers for citratecoated and PVP-coated AgNPs. Gene expression profiles revealed that AgNO3 and AgNPs have distinct expression profiles suggesting different modes of toxicity. Major biological processes disrupted by the AgNPs include protein metabolism and signal transduction. In contrast, AgNO3 caused a downregulation of developmental processes, particularly in sensory development. Metal responsive and DNA damage repair genes were induced by the PVP AgNPs, but not the other treatments. In addition, two specific biomarkers were developed for the environmental detection of PVP AgNPs; although further verification under different environmental conditions is needed.
■
INTRODUCTION The development and commercialization of nanomaterials is proceeding rapidly. They have begun to revolutionize several industries including building materials, health and medicine, electronics, and green technologies.1 Nanoparticles (NPs) are defined as supramolecular compounds having at least one dimension
