RP17 Nanotechnology Environmental and Health Impacts
Thursday, 17 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall
(BUC-1117-812339) Nanoparticle absorption by the aquatic invertebrate, Ceriodaphnia dubia.
Buchanan, R1, Ingle, T1, Enger-Luster, N2, Alexander, R1, Farris, J2, 1 Arkansas BioSciences Institute, Arkansas State University, Jonesboro, AR, USA2 Environmental Sciences Program, Arkansas State University, Jonesboro, AR, USA
ABSTRACT- Fluorescence microscopy of Ceriodaphnia dubia exposed to picomolar concentrations of a fluorescent nanoparticle (Q-dots®, Quantum Dot Corp, Hayward CA) shows that nanoparticles are absorbed by this aquatic invertebrate so often used in assessing environmental effects. Nanoparticles (0.5-5 
l, total nanoparticle concentration 10-100 pM) suspended in aqueous buffer were added to moderately hard water containing adult C. dubia. Individual C. dubia were examined after 15 min, 1, 2, and 4 h using a Nikon epifluorescence microscope (excitation 
465-495 nm; emission 515-555 nm). Fluorescence of individual C. dubia increased with exposure time. Internal structures were clearly visible and differentially labeled in treated animals suggesting that particles were absorbed into body tissues. For example, the heart exhibited no visible fluorescence after 4 h, while the digestive tract and muscles of the thorax were brightly fluorescent. By introducing C. dubia into moderately hard water containing a suspension of nanoparticles (10-100 pM) in an immiscible solvent (decane) the fluorescent characteristics of animals coated with particles were examined. Individuals so exposed exhibited bright fluorescence but internal organs were obscured by adherent particles. Recent studies on the toxic effects of nanotechnology products have suggested the need for more research into the environmental and health effects of engineered nanomaterials. Information about the absorbance of nanoparticles by organisms in an aquatic environment may aid future efforts to characterize the toxicity of such particles.
Key words: nanomaterials, nanoparticles, fluorescence microscopy, C. dubia