Thrust 4: Phototoxicity Assessment of Graphene Oxide Nanosheets using Zebrafish Embryos as a Vertebrate Model (2014)

Min-Sik Kim, Jamie Wheeler, Joel A. Pedersen, Robert J. Hamers, Richard E. Peterson, Warren Heideman

Representative micrographs of 120 hpf larvae exposed to fishwater (control) or GO (500 µg/mL) with or without illumination; PE: pericardial edema, YE: yolk sac edema, CFM: craniofacial malformation, OY: opaque yolk and BAC: body axis curvature.

Graphene oxide (GO) is a nanomaterial that has attracted substantial interest because of its unique physical, chemical, electronic, mechanical, optical and thermal properties. GO has a wide range of potential applications including biotechnology, cancer therapy, and wastewater treatment. However, little is known about how interactions with the environment can affect GO chemistry, nor do we know whether GO poses health risks to organisms that will ultimately come in contact with GO. We have used developing zebrafish to investigate potential toxicity of GO.

We find that the combination of GO exposure and simulated sunlight illumination can produce toxic responses in the zebrafish embryo. Graphene oxide exposure during development has the potential to produce malformations. Photo-activated GO produces reactive oxygen species, which in turn cause cellular oxidative stress, DNA damage, and cell death. This likely contributes to the photo-enhanced toxicity. Our findings show that sunlight is an important factor in determining the toxicity of nanomaterials, and environmental factors needs to be considered when assessing the risk and potential hazards of nanomaterials to human health and the environment.