Toxicity Studies on Graphene-Based Nanomaterials in Aquatic Organisms: Current Understanding.

Nemi Malhotra,Chung-Der Hsiao,Oliver B Villaflores,Tzong-Rong Ger,Petrus Siregar,Gilbert Audira,Jiann-Shing Lee

doi:10.3390/molecules25163618

Abstract

Graphene and its oxide are nanomaterials considered currently to be very promising because of their great potential applications in various industries. The exceptional physiochemical properties of graphene, particularly thermal conductivity, electron mobility, high surface area, and mechanical strength, promise development of novel or enhanced technologies in industries. The diverse applications of graphene and graphene oxide (GO) include energy storage, sensors, generators, light processing, electronics, and targeted drug delivery. However, the extensive use and exposure to graphene and GO might pose a great threat to living organisms and ultimately to human health. The toxicity data of graphene and GO is still insufficient to point out its side effects to different living organisms. Their accumulation in the aquatic environment might create complex problems in aquatic food chains and aquatic habitats leading to debilitating health effects in humans. The potential toxic effects of graphene and GO are not fully understood. However, they have been reported to cause agglomeration, long-term persistence, and toxic effects penetrating cell membrane and interacting with cellular components. In this review paper, we have primarily focused on the toxic effects of graphene and GO caused on aquatic invertebrates and fish (cell line and organisms). Here, we aim to point out the current understanding and knowledge gaps of graphene and GO toxicity.

Highlights

Graphene is an allotrope of carbon [1]
In a study to test the toxicity of graphene oxide (GO) and multi-walled carbon nanotubes (MWNTs), the results showed that GO has moderate toxicity to organisms as it inhibited growth and caused slight hatching delay among zebrafish embryos at 50 mg/L but did not depict significant increase on apoptosis in the embryo, whereas MWNTs’ toxicity demonstrated strong inhibition of cell proliferation and serious morphological defects in developing embryos even at lower dose of 25 mg/L
We hereby summarize that research of graphene and GO toxicity duration of exposure are very critical

Summary

Introduction

Graphene is an allotrope of carbon [1]. It is defined as single layer of carbon sheet with a hexagonal packed lattice structure with sp hybridized carbon atoms tightly packed in a 2D honeycomb lattice, which provides large surface area on both sides of the planar axis [2]. The unmodified basal plane sites of graphene comprise free surface π electrons that are hydrophobic [3]. The hydrophobicity of the graphene is strongly thickness-dependent, with single-layer graphene being significantly more hydrophilic than its thicker counterparts [4]. The ideal graphene is a single-layer carbon atom held together by covalent bonds. It is difficult to isolate a single layer of graphene, graphene is

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