In vivo Biomodification of Lipid-Coated Carbon Nanotubes by

Environ. Sci. Technol. 2007, 41, 3025-3029

In vivo Biomodification of Lipid-Coated Carbon Nanotubes by Daphnia magna AARON P. ROBERTS,† ANDREW S. MOUNT,‡ BRANDON SEDA,‡ JUSTIN SOUTHER,‡ RUI QIAO,§ SIJIE LIN,| PU CHUN KE,| APPARAO M. RAO,| AND S T E P H E N J . K L A I N E * ,‡ Department of Biological Sciences, University of North Texas, Denton, Texas 76203, and Department of Biological Sciences, Department of Mechanical Engineering, and Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634

This study examined the interactions between Daphnia magna and a water-soluble, lysophophatidylcholine coated single-walled carbon nanotube. D. magna were able to ingest the nanotubes through normal feeding behavior and utilize the lysophophatidylcholine coating as a food source. D. magna were able to modify the solubility of the nanotube, likely through digestion of the lipid coating. This study provides evidence of biomodification of a carbonbased nanomaterial by an aquatic organism. The modification significantly altered the physical properties of the nanomaterial in freshwater. Acute toxicity was observed only in the highest test concentrations. These are important findings related to determining the behavior and potential toxicity of coated nanomaterials released into the environment.

Introduction Advancements in the science of engineered nanoparticles (materials with at least one dimension