Upon Exposure to Cu Nanoparticles, Accumulation of Copper in the Isopod <i>Porcellio scaber</i> Is Due to the Dissolved Cu Ions Inside the Digestive Tract

The fate of nanoparticles in organisms is of significant interest. In the current work, we used a test system with terrestrial isopods (<i>Porcellio scaber</i>) fed with food spiked with Cu NPs or soluble Cu salt for 14 days. Two different doses were used for spiking to yield final concentrations of 2000 and 5000 μg Cu/g dry food. After the exposure period, part of the exposed group of animals was transferred to clean food to depurate. Cu content was analyzed in the digestive glands, gut, and the ‘rest’ of the body. Similar patterns of (i) assimilated and depurated amounts of Cu, (ii) Cu body distribution, and (iii) effect on isopods feeding behavior were observed regardless of whether the animals were fed with Cu NPs or soluble Cu salt spiked food. Thus, Cu ions and not Cu NPs were assimilated by the digestive gland cells. Solubilization of the Cu NPs applied to the leaves was also analyzed with chemical methods and recombinant Cu-sensing bacteria. The comparison of the in vitro data on solubilization of Cu NPs and in vivo data on Cu accumulation in the animal tissues showed that about 99% of accumulated copper ions was dissolved from ingested Cu NPs in the digestive system of isopods

FTIR microscopy reveals distinct biomolecular profile of crustacean digestive glands upon subtoxic exposure to ZnO nanoparticles

<p>Biomolecular profiling with Fourier-Transform InfraRed Microscopy was performed to distinguish the Zn²⁺-mediated effects on the crustacean (<i>Porcellio scaber</i>) digestive glands from the ones elicited by the ZnO nanoparticles (NPs). The exposure to ZnO NPs or ZnCl₂ (1500 and 4000 µg Zn/g of dry food) activated different types of metabolic pathways: some were found in the case of both substances, some only in the case of ZnCl₂, and some only upon exposure to ZnO NPs. Both the ZnO NPs and the ZnCl₂ increased the protein (∼1312 cm⁻¹; 1720–1485 cm⁻¹/3000–2830 cm⁻¹) and RNA concentration (∼1115 cm⁻¹). At the highest exposure concentration of ZnCl₂, where the effects occurred also at the organismal level, some additional changes were found that were not detected upon the ZnO NP exposure. These included changed carbohydrate (most likely glycogen) concentrations (∼1043 cm⁻¹) and the desaturation of cell membrane lipids (∼3014 cm⁻¹). The activation of novel metabolic pathways, as evidenced by changed proteins’ structure (at 1274 cm⁻¹), was found only in the case of ZnO NPs. This proves that Zn²⁺ are not the only inducers of the response to ZnO NPs. Low bioavailable fraction of Zn²⁺ in the digestive glands exposed to ZnO NPs further supports the role of particles in the ZnO NP-generated effects. This study provides the evidence that ZnO NPs induce their own metabolic responses in the subtoxic range.</p

Cellular Internalization of Dissolved Cobalt Ions from Ingested CoFe₂O₄ Nanoparticles: In Vivo Experimental Evidence

With a model invertebrate animal, we have assessed the fate of magnetic nanoparticles in biologically relevant media, i.e., digestive juices. The toxic potential and the internalization of such nanoparticles by nontarget cells were also examined. The aim of this study was to provide experimental evidence on the formation of Co²⁺, Fe²⁺, and Fe³⁺ ions from CoFe₂O₄ nanoparticles in the digestive juices of a model organism. Standard toxicological parameters were assessed. Cell membrane stability was tested with a modified method for measurement of its quality. Proton-induced X-ray emission and low energy synchrotron radiation X-ray fluorescence were used to study internalization and distribution of Co and Fe. Co²⁺ ions were found to be more toxic than nanoparticles. We confirmed that Co²⁺ ions accumulate in the hepatopancreas, but Fe^<i>n</i>+ ions or CoFe₂O₄ nanoparticles are not retained in vivo. A model biological system with a terrestrial isopod is suited to studies of the potential dissolution of ions and other products from metal-containing nanoparticles in biologically complex media

Cellular Internalization of Dissolved Cobalt Ions from Ingested CoFe₂O₄ Nanoparticles: In Vivo Experimental Evidence

With a model invertebrate animal, we have assessed the fate of magnetic nanoparticles in biologically relevant media, i.e., digestive juices. The toxic potential and the internalization of such nanoparticles by nontarget cells were also examined. The aim of this study was to provide experimental evidence on the formation of Co²⁺, Fe²⁺, and Fe³⁺ ions from CoFe₂O₄ nanoparticles in the digestive juices of a model organism. Standard toxicological parameters were assessed. Cell membrane stability was tested with a modified method for measurement of its quality. Proton-induced X-ray emission and low energy synchrotron radiation X-ray fluorescence were used to study internalization and distribution of Co and Fe. Co²⁺ ions were found to be more toxic than nanoparticles. We confirmed that Co²⁺ ions accumulate in the hepatopancreas, but Fe^<i>n</i>+ ions or CoFe₂O₄ nanoparticles are not retained in vivo. A model biological system with a terrestrial isopod is suited to studies of the potential dissolution of ions and other products from metal-containing nanoparticles in biologically complex media