Toxicity of Oxidatively Degraded Quantum Dots
Once released into the environment, engineered nanoparticles (eNPs) are subjected to processes that may alter their physical or chemical properties, potentially altering their toxicity vis-à-vis the as-synthesized materials. We examined the toxicity to zebrafish embryos of CdSe core /ZnS shell quant...
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Published in | Environmental science & technology Vol. 47; no. 16; pp. 9132 - 9139 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
02.08.2013
|
Online Access | Get full text |
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Summary: | Once released into the environment, engineered nanoparticles (eNPs) are subjected to processes that may alter their physical or chemical properties, potentially altering their toxicity vis-à-vis the as-synthesized materials. We examined the toxicity to zebrafish embryos of CdSe
core
/ZnS
shell
quantum dots (QDs) before and after exposure to an
in vitro
chemical model designed to simulate oxidative weathering in soil environments based on a reductant-driven Fenton’s reaction. Exposure to these oxidative conditions resulted in severe degradation of the QDs: the Zn shell eroded, Cd
2+
and selenium were released, and amorphous Se-containing aggregates were formed. Weathered QDs exhibited higher potency than did as-synthesized QDs. Morphological endpoints of toxicity included pericardial, ocular and yolk sac edema, non-depleted yolk, spinal curvature, tail malformations, and craniofacial malformations. To better understand the selenium-like toxicity observed in QD exposures, we examined the toxicity of selenite, selenate and amorphous selenium nanoparticles (SeNPs). Selenite exposures resulted in high mortality to embryos/larvae while selenate and SeNPs were non-toxic. Co-exposures to SeNPs + CdCl
2
resulted in dramatic increase in mortality and recapitulated the morphological endpoints of toxicity observed with weathered QD exposures. Cadmium body burden was increased in larvae exposed to weathered QDs or SeNP + CdCl
2
suggesting the increased potency of weathered QDs was due to selenium modulation of cadmium toxicity. Our findings highlight the need to examine the toxicity of eNPs after they have undergone environmental weathering processes. |
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Bibliography: | Current address: AkzoNobel, Brewster, NY Current address: Lancaster Laboratories, Lancaster, PA Current address: Department of Chemistry, Albion College, Albion, MI Current address: Department of Biology, University of Wisconsin – La Crosse, La Crosse, WI |
ISSN: | 0013-936X 1520-5851 |
DOI: | 10.1021/es304987r |