Interaction of silver nanoparticles with algae and fish cells: a side by side comparison

Background: Silver nanoparticles (AgNP) are widely applied and can, upon use, be released into the aquatic environment. This raises concerns about potential impacts of AgNP on aquatic organisms. We here present a side by side comparison of the interaction of AgNP with two contrasting cell types: algal cells, using the algae Euglena gracilis as model, and fish cells, a cell line originating from rainbow trout (Oncorhynchus mykiss) gill (RTgill-W1). The comparison is based on the AgNP behavior in exposure media, toxicity, uptake and interaction with proteins. Results: (1) The composition of exposure media affected AgNP behavior and toxicity to algae and fish cells. (2) The toxicity of AgNP to algae was mediated by dissolved silver while nanoparticle specific effects in addition to dissolved silver contributed to the toxicity of AgNP to fish cells. (3) AgNP did not enter into algal cells; they only adsorbed onto the cell surface. In contrast, AgNP were taken up by fish cells via endocytic pathways. (4) AgNP can bind to both extracellular and intracellular proteins and inhibit enzyme activity. Conclusion: Our results showed that fish cells take up AgNP in contrast to algal cells, where AgNP sorbed onto the cell surface, which indicates that the cell wall of algae is a barrier to particle uptake. This particle behaviour results in different responses to AgNP exposure in algae and fish cells. Yet, proteins from both cell types can be affected by AgNP exposure: for algae, extracellular proteins secreted from cells for, e. g., nutrient acquisition. For fish cells, intracellular and/or membrane-bound proteins, such as the Na+/K+-ATPase, are susceptible to AgNP binding and functional impairment.

Chemical Aspects of Nanoparticle Ecotoxicology

Renata Behra, Kristin Schirmer, Hannah Inka Schug, Laura Sigg, Yang Yue

Nanoecotoxicology strives to understand the processes and mechanisms by which engineered nanoparticles (ENP) may exert toxic effects on aquatic organisms. Detailed knowledge of the chemical reactions of nanoparticles in the media and of their interactions with organisms is required to understand these effects. The processes of agglomeration of nanoparticles, of dissolution and release of toxic metal ions, and of production of reactive oxygen species (ROS) are considered in this article. Important questions concern the role of uptake of nanoparticles in various organisms, in contrast to uptake of ions released from nanoparticles and to nanoparticle attachment to organism surfaces. These interactions are illustrated for effects of silver nanoparticles (AgNP), cerium oxide (CeO2 NP) and titanium dioxide (TiO2 NP), on aquatic organisms, including algae, biofilms, fish cells and fish embryos.

Swiss Chemical Soc2014

Silver nanoparticle-protein interactions in intact rainbow trout gill cells

Renata Behra, Kristin Schirmer, Laura Sigg, Yang Yue

Upon contact with biota, nanoparticles can bind to proteins, which coat the nanoparticles and form a nanoparticle-protein corona. Knowledge of corona proteins is therefore important for a mechanistic understanding of how nanoparticles interact with biomolecules in cells. Here we present the first study to reveal the identity of corona proteins from silver nanoparticle (AgNPs)-exposed living vertebrate cells. The cells are from a rainbow trout (Oncorhynchus mykiss) gill cell line, RTgill-W1, representing the interface between the aquatic environment and one of its model species. Subcellular fractionation allowed AgNP-protein corona complexes to be recovered from intact subcellular compartments and proteins lysed from the AgNPs to be detected by mass spectrometry. The identified proteins mark the trail of AgNPs processing in the cells like a forensic fingerprint: the cells take up the AgNPs via endocytic processes and store the particles in endosomal/lysosomal compartments. Moreover, stress response proteins were recovered in the AgNPs protein corona. In this way, we established a list of AgNPs susceptible proteins which can be investigated further in targeted nanoparticle-protein interaction. As a proof of principle, we demonstrate that Na+/K+-ATPase, identified from the corona and a known key protein in ion regulation in gill cells, is inhibited in its activity by AgNPs, confirming previously published in vivo experiments. The developed methodology is broadly applicable to other nanoparticles and cell types, representing a valuable tool for mechanistic nanoparticle-cell interaction studies, ranging from environmental and human risk assessment to biomedicine. In this way, our research also contributes to safer particle design.

Royal Soc Chemistry2016

In-vitro digestion of Tire and Road Wear Particles: Bioavailability of metals and Polycyclic Aromatic Hydrocarbons

Florian Frédéric Vincent Breider, Benoît Jean Dominique Ferrari, Thibault Béranger Masset, Kristin Schirmer

The potential impact of Tire and Road Wear Particles (TRWP) on aquatic organisms has recently gained attention since the occurrence of TRWP in the aquatic environment has been observed in surface water and sediments of numerous regions. Moreover, the ingestion of TRWP by aquatic species, including fish, has recently been demonstrated. However, data regarding the bioavailability and toxicity of contaminants associated with these particles are still lacking. This study aimed (i) to characterize the solubilization potential of metals and PAHs from tire particles and TRWP in Simulated Gastric Fluids (SFG) and Simulated Intestinal Fluids (SIF) designed to mimic Oncorhynchus mykiss (Rainbow Trout) gut conditions and (ii) to assess the impact of influencing factors such as co-ingestion of natural food organic matter on the compounds solubilization. Our results showed that solubilization of all metals and PAHs were enhanced by up to 10-fold in simulated gut fluids compared to solubilization in the control (phosphate buffer saline solution). Zn was highly solubilized after an in-vitro digestion of 24-h with a final concentration in SIF of 3,2 µg.L-1 corresponding to 23 % of the total Zn concentration in TRWP. Five PAHs (Fluoranthene, Phenanthrene, Pyrene, Benzo (e) Pyrene and Benzo (g,h,i) perylene) were quantified in SIF after an incubation time of 24-h and the concentration of individual PAHs in SIF ranged from 42 to 3092 ng.L-1 which represented 0,4 – 1,5 % of their total concentration measured in tire particles. Metals were highly solubilized by the acidic SGF (pH = 2) but only a weak solubilization was observed in neutral SIF (pH = 7,4). Contrastingly, PAHs were not solubilized in SGF and highly solubilized in SIF which was proved to contain high quantities of proteins and surfactants forming micelles. This emphasise the importance of pH in the solubilization of metals and of bile surfactants and organic matter in the solubilization of PAHs from TRWP and brings new insights on the bioavailability of metals and organic pollutants from TRWP. Overall, our results demonstrate the importance of accounting for the ingestion of TRWP as an important route of exposure to metals and PAHs for aquatic organisms. As the solubilization of potential toxic compounds was greatly enhanced by the gut fluids and leads to bioavailability of these compounds, further studies investigating the uptake by the epithelial cells and transfer throughout the whole organism will be performed.

2021

In-vitro digestion of Tire and Road Wear Particles: Bioavailability of metals and Polycyclic Aromatic Hydrocarbons

Florian Frédéric Vincent Breider, Benoît Jean Dominique Ferrari, Thibault Béranger Masset, Kristin Schirmer

2021