Developmental effects of two different copper oxide nanomaterials in sea urchin (Lytechinus pictus) embryos

Abstract

Copper oxide nanomaterials (nano-CuOs) are widely used and can be inadvertently introduced into estuarine and marine environments. We analyzed the effects of different nano-CuOs (a synthesized and a less-pure commercial form), as well as ionic copper (CuSO₄) on embryo development in the white sea urchin, a well-known marine model. After 96 h of development with both nano-CuO exposures, we did not detect significant oxidative damage to proteins but did detect decreases in total antioxidant capacity. We show that the physicochemical characteristics of the two nano-CuOs play an essential role in their toxicities. Both nano-CuOs were internalized by embryos and their differential dissolution was the most important toxicological parameter. The synthesized nano-CuO showed greater toxicity (EC₅₀ = 450 ppb of copper) and had increased dissolution (2.5% by weight over 96 h) as compared with the less-pure commercial nano-CuO (EC₅₀ = 5395 ppb of copper, 0.73% dissolution by weight over 96 h). Copper caused specific developmental abnormalities in sea urchin embryos including disruption of the aboral-oral axis as a result in changes to the redox environment caused by dissolution of internalized nano-CuO. Abnormal skeleton formation also occurred.

• Embryonic axis disruption
• nanoparticle dissolution
• oxidative stress
• sea urchin embryo development

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article. This research is part of the University of California Center for the Environmental Implications of Nanotechnology (UC CEIN) and was supported by the National Science Foundation and the Environmental Protection Agency under Cooperative Agreement Number DBI-0830117 and DBI-1266377. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation or the Environmental Protection Agency. This work has not been subjected to EPA review and no official endorsement should be inferred. The authors would like to thank the funding from the UC MEXUS-CONACyT Postdoctoral Research Fellowship program (C. Torres) and Carol Vines for technical support.

Supplementary material available online.

Figures S1–S5 and Tables S1 and S2.