Toxicity Evaluation of Graphene Oxide and Titania Loaded Nafion Membranes in Zebrafish

Abstract

The use of nanomaterials in several application fields has received in the last decades a great attention due to their peculiar properties, but also raised many doubts about possible toxicity when these materials are used for some specific applications, such as water purification. Indeed a careful investigation is needed in order to exclude possible harmful side effects related to the use of nanotechnology. Nanoparticles effects on the marine organisms may depend on their chemical composition, size, surface structure, solubility, shape and how the individual nanoparticles aggregate together. In order to make the most of their potential, without polluting the environment, many researchers are trying to trap them into some kind of matrix that keeps them active but avoids their dispersion in the environment. In this study we have tested nanocomposite membranes prepared using Nafion polymer combined with various fillers, such as anatase-type TiO2 nanoparticles and graphene oxide. The non-toxicity of these nanocomposites, already shown to be effective for water purification applications in our previous studies, was recognized by testing the effect of the different materials on zebrafish embryos. Zebrafish was considered an excellent model for ecotoxicological studies and for this motivation zebrafish embryos were exposed to different concentrations of free nanoparticles and to the nanocomposite membranes. As biomarkers of exposure, we evaluated the expression of heme-oxygenase 1 and inducible Nitric Oxide Synthases by immunohistochemistry and gene expression. Embryo toxicity test showed that nor sublethal effects neither mortality were caused by the different nanoparticles and nano-systems tested. Only zebrafish larvae exposed to free nanoparticles have shown a different response to antibodies anti-heme-oxygenase 1 and anti- inducible Nitric Oxide Synthases. The immunolocalization analysis in fact has highlighted an increase in the synthesis of these biomarkers.

Graphene-Based Nanomaterials Toxicity in Fish

“…In contrast to these observations, no obvious oxidative stress with regard to alteration in the activities of SOD, CAT, GSH and MDA enzymes was observed in the liver of adult zebrafish exposed to 250 μg/L sFLG for 24, 48, and 72 h (Lu et al, 2017). Moreover, the enhancement of iNOS mRNA and protein in zebrafish larvae exposed to GO (Pecoraro et al 2018) indicated that reactive nitrogen species (RNS)–mediated pathways were also involved in GO-induced toxicity. HO, the enzyme catalyzes the degradation of heme, is also enhanced by GO (Pecoraro et al, 2018).…”

“…Moreover, the enhancement of iNOS mRNA and protein in zebrafish larvae exposed to GO (Pecoraro et al 2018) indicated that reactive nitrogen species (RNS)–mediated pathways were also involved in GO-induced toxicity. HO, the enzyme catalyzes the degradation of heme, is also enhanced by GO (Pecoraro et al, 2018). Although the data are contradictory, all these studies indicate that generation of ROS is able to modulate the expression and functions of antioxidant enzymes either directly or indirectly and have a potential impact on cellular MDA and GSH concentrations.…”

“…No alteration in mortality, growth, brain morphology, pharyngeal arches and jaw structures, heart, fins, notochord, somites, body shape, cardiovascular function, yolk sac and locomotor functions were observed. However, both HO and iNOS mRNA and proteins levels were enhanced by GO at 96 hpf (Pecoraro et al 2018) which indicate that the generation of reactive nitrogen species (RNS) in zebrafish larvae can be induced by GO flakes during development.…”

Toxicity assessment of nano‐TiO2inApis melliferaL., 1758: histological and immunohistochemical assays

“…We evaluated the toxicity of the TiO 2 nanoparticles in A. mellifera because this xenobiotic is used in a wide range of products, and because there is scant published literature about the toxicity of NPs on terrestrial arthropods. Several studies in literature have shown the non‐toxicity of these nanoparticles in some model organisms (Brundo et al, ; Pecoraro et al, , ; Scuderi et al, ). Our findings proved, titanium dioxide nanoparticles are toxic to all the concentrations considered.…”

Evaluation of the effects of silver nanoparticles on Danio rerio cornea: Morphological and ultrastructural analysis

“…Several studies on animal models have shown that NPs can be potentially toxic (Hu et al, ; Lankveld et al, ), and that toxicity of NPs depends certainly on their size (Lankveld et al, ). Among the different animal models, zebrafish or Danio rerio is considered an excellent model for nanotoxicity studies for some particular features of these animals (Brundo et al, ; Lee, Nallathamby, Browning, Osgood, & Xu, ; Pecoraro et al, ; Pecoraro et al, ; Pecoraro et al, ; Salvaggio et al, ; Sarasamma et al, ; Zhao et al, ).…”