Functionalized nanomaterials are a group of emerging contaminants which effects on aquatic organism are the target of our current investigation. Oxidative stress, particle uptake, survival and reproductive impairment are biological processes that have been reported in the literature to be disturbed in aquatic invertebrates by these functionalized nanomaterials. Our goal was to evaluate the effects of functionalized nanomaterials on membrane destabilization and subsequent oxidative stress using an in vivo approach. To begin to understand the effects of functionalized nanoparticles uptake on the aquatic invertebrate gut, we exposed the filter-feeding crustacean (Daphnia magna) to different sublethal concentrations of gold and diamond nanoparticles carrying two different surface functionalized groups, CTAB (cetyltrimethylammonium bromide) and PAH (polyallylamine hydrochloride) for 24 and 48 hours. Dissected guts from exposed individuals were used in two different assays. Preliminary experiments were performed using acridine orange (AO) and diamidino-2-phenylindole-dihydrochloride (DAPI) assay to evaluate increase in cell membrane permeability and concluding assay measured the production of reactive oxygen species (ROS) by staining dissected guts with dihydroethidium (DHE) or dichlorodihydrofluorescein diacetate (H2DCFDA). All stained tissues were imaged using fluorescence microscopy. We determined that membrane permeability and production of reactive oxygen species increased with higher nanoparticle concentration and longer time exposure. The outcome of this study reveals, for the first time, that it is possible to evaluate gut membrane disruption and production of reactive oxygen species in vivo in aquatic invertebrates. This outcome may help to explain other endpoint effects observed in aquatic invertebrates exposed to functionalized nanoparticles and highlight the role of the reactive oxygen species on mortality, offspring production and other biological functions in D. magna.

Interactions of functionalized nanomaterials on membrane gut of <i>Daphnia magna</i>

246th National Meeting (2013)

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Interactions of functionalized nanomaterials on membrane gut of Daphnia magna