Impact of chemical composition of ecotoxicological test media on the stability and aggregation status of silver nanoparticles

Metreveli, George; Frombold, Bianca; Seitz, Frank; Grün, Alexandra; Philippe, Allan; Rosenfeldt, Ricki R.; Bundschuh, Mirco; Schulz, Ralf; Manz, Werner; Schaumann, Gabriele E.

doi:10.1039/c5en00152h

Cited by 46 publications

(40 citation statements)

References 67 publications

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“…This result is in agreement with a previous study showing that the divalent cation Mg 2+ could efficiently decrease the zeta potential of PVP‐coated AgNPs . The R7.7 buffer contains 15 × 10 −3 m Mg 2+ that is higher than the critical coagulation concentration of Mg 2+ in solution for AgNPs . In our present study, Mg 2+ could therefore induce the aggregation of AgNPs and decrease of the zeta potential.…”

Section: Discussionsupporting

confidence: 93%

Interaction between Silver Nanoparticles and Two Dehydrogenases: Role of Thiol Groups

Jiang

Zhang

Lü

et al. 2019

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Widely used silver nanoparticles (AgNPs) are readily accessible to biological fluids and then surrounded by proteins. However, interactions between AgNPs and proteins are poorly understood. Two dehydrogenases, glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) and malate dehydrogenase (MDH), are chosen to investigate these interactions. Ag bound to thiol groups of these enzymes significantly decreases the number of free thiols available. Dose‐dependent inhibition of enzyme activities is observed in both AgNPs and Ag+ treatments. Based on the concentration required to inhibit 50% activity, GAPDH and MDH are 24–30 fold more sensitive to Ag+ than to AgNPs suggesting that the measured 4.2% Ag+ containing AgNPs can be responsible for the enzymes inhibition. GAPDH, with a thiol group in its active site, is more sensitive to Ag than MDH, displaying many thiol groups but none in its active site, suggesting that thiol groups at the active site strongly determines the sensitivity of enzymes toward AgNPs. In contrast, the dramatic changes of circular dichroism spectra show that the global secondary structure of MDH under AgNPs treatment is more altered than that of GAPDH. In summary, this study shows that the thiol groups and their location on these dehydrogenases are crucial for the AgNPs effects.

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Section: Discussionsupporting

confidence: 93%

Interaction between Silver Nanoparticles and Two Dehydrogenases: Role of Thiol Groups

Jiang

Zhang

Lü

et al. 2019

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“…These results indicate that a lower amount of Ag + ions were released from citrate‐coated AgNP during the first hours of the experiment, although the total silver concentration of AgNP was higher. The release of Ag + ions from AgNP can be controlled by artificial surface blocking induced by NOM ( Metreveli et al, ). Furthermore, Ag + ions can be slowly released from AgNP and continuously precipitated by the mono‐ or divalent cations, leading to the formation of less toxic compounds, such as AgCl or AgS 2 .…”

Section: Discussionmentioning

confidence: 99%

“…Medium‐mediated impacts on nanoparticle aggregation, deposition and stabilization processes are currently under intensive investigation ( Schaumann et al, ; Metreveli et al, ). The ionic strength of amoeba saline is low compared to that of media commonly applied in ecotoxicological test systems ( Metreveli et al, ). Nevertheless, reduction of the electric double layer of AgNP and the resulting aggregation according to the DLVO theory occurred.…”

Section: Discussionmentioning

confidence: 99%

“…Medium-mediated impacts on nanoparticle aggregation, deposition and stabilization processes are currently under intensive investigation (Schaumann et al, 2015;Metreveli et al, 2016). The ionic strength of amoeba saline is low compared to that of media commonly applied in ecotoxicological test systems .…”

Section: Ag + Ions Released From Agno 3 Caused Stronger Effects Than mentioning

confidence: 99%

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Assessment of the effect of silver nanoparticles on the relevant soil protozoan genus Acanthamoeba

Grün

Scheid

Hauröder

et al. 2017

J. Plant Nutr. Soil Sci.

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Silver nanoparticles (AgNP) are used in a broad range of consumer products and industrial applications. During the regular product life cycle and disposal, AgNP are continuously released into the environment. Hence, the aim of this study was to investigate the potential ecotoxicological effects of AgNP exposure on amoebae. The Acanthamoeba castellanii ATCC 30234 strain and environmental isolate Acanthamoeba strain C5/2, which are both affiliated with genotype T4, were chosen as representatives of ecologically important soil protozoan organisms. The amoebae were exposed to citrate‐stabilized AgNP (30 and 70 nm in size) for 24 h and 96 h at concentrations ranging from 600 µg L−1 to 20 mg L−1. A newly adopted cell culture based microscopic assay was applied to assess the adherence ability of the amoeba trophozoites. The general metabolic activity of Acanthamoeba was determined to be a second independent endpoint by means of intracellular reduction of the redox dye AlamarBlue®. The fate of AgNP within the amoebae and test solutions was visualized by light‐ and transmission electron microscopy (TEM). Both Acanthamoeba strains showed a significant dose‐dependent decrease of adherence ability (p < 0.04) and metabolic activity (p < 0.01) after 96 h of AgNP exposure. The environmental Acanthamoeba strain C5/2 lost both its adherence ability and metabolic activity at lower AgNP concentrations than the type strain, indicating a higher sensitivity to ionic silver. This was confirmed by the application of AgNO3, provoking a higher effect level in strain C5/2. AgNP was visualized intracellularly by transmission electron microscopy within the cytoplasm of Acanthamoeba. This is the first report to show the ecotoxicological effects of short‐term AgNP exposure on the soil protist Acanthamoeba, causing both changes in the adherence ability and metabolic activity of this amoeba. This combined approach may be a powerful tool in the future for predicting potential harmful ecotoxicological effects of AgNP exposure using soil protozoans.

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“…S1). This was probably due to the stabilizing (steric) effects of PVP (Topuz et al, 2015;Wang et al, 2005) and organic acids in natural water that may adsorb on the surface of Ag NPs, inducing electrosteric repulsion and increasing the stability of NPs even in the presence low levels of chlorides (Metreveli et al, 2016;Topuz et al, 2015).…”

Section: Characteristics Of Ag and Cuo Nanoparticles In Natural Watermentioning

confidence: 98%

Natural water as the test medium for Ag and CuO nanoparticle hazard evaluation: An interlaboratory case study

Heinlaan

Muna

Knöbel

et al. 2016

Environmental Pollution

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Impact of chemical composition of ecotoxicological test media on the stability and aggregation status of silver nanoparticles

Abstract: Aggregation status of Ag NPs in ecotoxicological test media is controlled by the Ca2+/Mg2+ ratio, presence of Cl− and Br− and NOM quality.

Cited by 46 publications

References 67 publications

Interaction between Silver Nanoparticles and Two Dehydrogenases: Role of Thiol Groups

Interaction between Silver Nanoparticles and Two Dehydrogenases: Role of Thiol Groups

Assessment of the effect of silver nanoparticles on the relevant soil protozoan genus Acanthamoeba

Natural water as the test medium for Ag and CuO nanoparticle hazard evaluation: An interlaboratory case study

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