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Formation of Low Molecular Weight Products During Environmental Transformation of Graphene Oxide Modulates Toxicity in Aquatic Species
Citation:
Henderson, Matt, J. Spear, R. Seim, R. Zepp, Brad Acrey, AND D. Bouchard. Formation of Low Molecular Weight Products During Environmental Transformation of Graphene Oxide Modulates Toxicity in Aquatic Species. 2020 SOT Virtual Meeting, Anaheim, CA, March 15 - 19, 2020.
Impact/Purpose:
Poster presented at the 2020 SOT Annual Meeting and ToxExpo
Description:
Carbon-based nanoparticles (CNPs) are used extensively in industrial, consumer, and mechanical applications. Their unique structural properties provide novel opportunities to develop more robust and innovative commercial products including paints, fabrics, cosmetics and electronics. With increasing commercial use of CNPs, environmental exposure is growing increasingly common. Specifically, graphene oxide (GO) has been shown to compromise cell integrity via interactions with lipid membranes and subsequent induction of oxidative stress in vitro. An understanding of GO-membrane interactions and resulting potential of GO to perturb biological systems is crucial for estimating risk. To assess the exposure and toxicological implications of environmental transformations of GO in aquatic species, GO suspensions were photo-irradiated by simulated sunlight for up to 490 hrs. Fathead minnow (FHM) epithelial cells were exposed to both GO/reduced (rGO) suspensions as well as their filtrates. The formation of low molecular weight products (LMWPs) was assessed by mass spectrometry and metabolomic profiling was used to investigate the biological response in this ecologically relevant cell line. GO readily undergoes both direct and indirect photo-transformation processes and increasing time of irradiation increases the biological response of FHM cells. Both decreased size of GO (or rGO formation) as well as the formation of LMWPs are likely contributing to this cellular response. In FHM cells, GO induced changes in numerous markers of oxidative stress. Most biological pathways affected included perturbations in the citric acid cycle, glycolysis and amino acid metabolism. Removal of suspended GO/rGO via filtration still elicited a biological response in our test system. Mass spectral identification of the LMWPs suggested that the photo-production of polycyclic aromatic hydrocarbon (PAH)-like derivatives facilitate the measured response in FHM cells. Ultimately, identifying potential biomarkers of GO exposure and the development of exposure indices of GO and its photoproducts in human and ecologically relevant species will aid in accurately establishing risk.
