Influence of calcium and EDTA on copper ion bioavailability in copper nanoparticle toxicity tests improves understanding of nano-specific effects

Abstract

Metal-based nanoparticles (NPs) can release metal ions that are toxic to aquatic organisms; however, whether the toxicity is from metal ions rather than unique “nano-scale” effects of the NPs is unresolved. The present study aimed to compare the toxicity of Cu2+ and Cu-NPs in larval zebrafish ( Danio rerio) to clarify whether toxic effects are attributable to release of Cu ions and to determine the effect of the chelating agent ethylenediaminetetraacetic acid (EDTA) and calcium hardness (as CaCO3) on the Cu toxicity. First, the acute toxicity (96-h lethality) of Cu-NPs was determined in comparison to aqueous Cu in larvae exposed to CuSO4, and subsequently, sublethal tests with Cu-NPs and CuSO4 were conducted with additions of EDTA or calcium ions to evaluate alterations in expression of metallothionein-2 ( MT2) gene transcripts (quantitative real-time polymerase chain reaction). Acute toxicity of Cu in larvae exposed to CuSO4 was greater (LC50 = 226 µg Cu/L) than for larvae exposed to Cu-NPs (LC50 = 648 µg Cu/L). The expression of MT2 increased with Cu concentration ( p < 0.05), and the slope of the linear regression was significantly greater in fish exposed to CuSO4 (slope = 0.090) compared to Cu-NPs (slope = 0.011). Cu2+ was 2.9-fold more toxic than Cu-NPs. The presence of 5 mg/L EDTA and 220 mg/L CaCO3 significantly reduced the expression of MT2 (1.8-fold for EDTA, 2.3-fold for CaCO3) in larvae exposed to CuSO4. For larvae exposed to Cu-NPs, the presence of EDTA reduced the expression of MT2 (1.7-fold) relative to Cu-NP concentration. While Cu-NPs induced MT2 expression, the differences in concentration relationships of MT2 expression between Cu-NPs and CuSO4 indicated that factors other than release of Cu ions from Cu-NPs influenced acute toxicity of Cu-NPs. The conclusion drawn from this ecotoxicological risk assessment was that EDTA and calcium significantly decreased Cu toxicity in freshwater fish.

Engineered Toll-like Receptor Nanoagonist Binding to Extracellular Matrix Elicits Safe and Robust Antitumor Immunity

“…31−37 And Mt2 was downregulated in the EaCpG + radiotherapy treatment, indicating that EaCpG + radiotherapy treatment inhibited tumor cell migration. 38 Also, both EaCpG and the combination of radiotherapy + EaCpG increased the expression of Tnf, Tlr9, and Tlr1 compared to other treatments (Figure S17). Meanwhile, we found that radiotherapy alone led to positive regulation of programmed cell death, the intrinsic apoptotic signaling pathway (Figure S18), Afterward, we performed enrichment analysis of gene ontology (GO) and KEGG using Metascape, which revealed that EaCpG enhanced the pattern recognition receptor signaling pathway compared to pCpG treatment (Figure 4H, left panel).…”

“…Notably, EaCpG treatment increased the expressions of some interferon response genes such as Irf7, Oas2, Oas3, SIfn2, SIfn4, and SIfn8 (Figure F) compared to pCpG treatment. Ly6c2 (lymphocyte antigen 6 complex, locus2) and Cxcl10, the indicatives of immunotherapy response, were upregulated in EaCpG compared to pCpG. − EaCpG + radiotherapy treatment increased Fcrl5, Evi2b, Cd300e, Camk1d, Aif1, Bcl11b, and Traf3ip3 compared to pCpG + radiotherapy (Figure G), which are typically associated with innate immune activation, positive regulation of NK cell and neutrophil differentiation, and macrophage and T-lymphocyte activation. − And Mt2 was downregulated in the EaCpG + radiotherapy treatment, indicating that EaCpG + radiotherapy treatment inhibited tumor cell migration . Also, both EaCpG and the combination of radiotherapy + EaCpG increased the expression of Tnf, Tlr9, and Tlr1 compared to other treatments (Figure S17).…”

Do Nanoparticles of Calcium Disodium EDTA Minimize the Toxic Effects of Cadmium in Female Rats?

“…Detoxification of cadmium with EDTA has been shown to be therapeutically beneficial in humans and animals when done using established protocols. EDTA was found to decrease Cu toxicity in freshwater fish [ 17 ]. Moreover, application of EDTA to the Cd-treated seedlings reduces Cd-induced oxidative injuries by restricting Cd uptake; increasing nonprotein thiols concentration and upregulating most of the components of their antioxidant defense and glyoxalase systems [ 18 ].…”