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The impact of species and cell type on the nanosafety profile of iron oxide nanoparticles in neural cells

View Article: PubMed Central - PubMed

ABSTRACT

Background: While nanotechnology is advancing rapidly, nanosafety tends to lag behind since general mechanistic insights into cell-nanoparticle (NP) interactions remain rare. To tackle this issue, standardization of nanosafety assessment is imperative. In this regard, we believe that the cell type selection should not be overlooked since the applicability of cell lines could be questioned given their altered phenotype. Hence, we evaluated the impact of the cell type on in vitro nanosafety evaluations in a human and murine neuroblastoma cell line, neural progenitor cell line and in neural stem cells. Acute toxicity was evaluated for gold, silver and iron oxide (IO)NPs, and the latter were additionally subjected to a multiparametric analysis to assess sublethal effects.

Results: The stem cells and murine neuroblastoma cell line respectively showed most and least acute cytotoxicity. Using high content imaging, we observed cell type- and species-specific responses to the IONPs on the level of reactive oxygen species production, calcium homeostasis, mitochondrial integrity and cell morphology, indicating that cellular homeostasis is impaired in distinct ways.

Conclusions: Our data reveal cell type-specific toxicity profiles and demonstrate that a single cell line or toxicity end point will not provide sufficient information on in vitro nanosafety. We propose to identify a set of standard cell lines for screening purposes and to select cell types for detailed nanosafety studies based on the intended application and/or expected exposure.

Electronic supplementary material: The online version of this article (doi:10.1186/s12951-016-0220-y) contains supplementary material, which is available to authorized users.

No MeSH data available.


A concentration-dependent decrease in ATP content, as measured via the CellTiter GLO® assay, is observed for every NP-cell type combination tested. Results for the AuNPs (yellow), AgNPs (blue) and IONPs (red) are represented as mean ± standard error of the mean (SEM, n = 3,). Statistical significance is indicated when appropriate for each type of NP in the corresponding color of the graphs [*p < 0.05, AuNPs (yellow), AgNPs (blue) and IONPs (red)]
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Fig1: A concentration-dependent decrease in ATP content, as measured via the CellTiter GLO® assay, is observed for every NP-cell type combination tested. Results for the AuNPs (yellow), AgNPs (blue) and IONPs (red) are represented as mean ± standard error of the mean (SEM, n = 3,). Statistical significance is indicated when appropriate for each type of NP in the corresponding color of the graphs [*p < 0.05, AuNPs (yellow), AgNPs (blue) and IONPs (red)]

Mentions: In initial cell experiments, we evaluated cell viability following 24 h NP exposure with the CellTiter GLO® assay. In Fig. 1, a general concentration-dependent decrease in ATP signal can be observed for every evaluated NP—cell type combination. Although the extent of this decrease clearly varies, the onset of this downward trend depended on both the applied NP and the cell type. In all cell types, the most severe effect was observed following AuNP treatment, while the cells were least affected by the IONPs. The toxicity observed for the AgNPs can likely in part be explained in terms of Ag+-ion leaching [34]. In turn, the severe acute cytotoxicity induced by the AuNPs could possibly be attributed to genotoxicity due to direct interactions between the 3.8 nm diameter AuNPs and DNA [35]. In addition, note that determining NP concentrations is not straightforward, as various methods/models need to be applied for different NP materials (Additional file 1). This may affect the comparison of absolute concentrations of NPs of different materials and may additionally explain the severe toxicity observed here for the AuNPs. Given the limited loss of cell viability observed for the IONPs, the latter were selected for further evaluation of sublethal effects.Fig. 1


The impact of species and cell type on the nanosafety profile of iron oxide nanoparticles in neural cells
A concentration-dependent decrease in ATP content, as measured via the CellTiter GLO® assay, is observed for every NP-cell type combination tested. Results for the AuNPs (yellow), AgNPs (blue) and IONPs (red) are represented as mean ± standard error of the mean (SEM, n = 3,). Statistical significance is indicated when appropriate for each type of NP in the corresponding color of the graphs [*p < 0.05, AuNPs (yellow), AgNPs (blue) and IONPs (red)]
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5017038&req=5

Fig1: A concentration-dependent decrease in ATP content, as measured via the CellTiter GLO® assay, is observed for every NP-cell type combination tested. Results for the AuNPs (yellow), AgNPs (blue) and IONPs (red) are represented as mean ± standard error of the mean (SEM, n = 3,). Statistical significance is indicated when appropriate for each type of NP in the corresponding color of the graphs [*p < 0.05, AuNPs (yellow), AgNPs (blue) and IONPs (red)]
Mentions: In initial cell experiments, we evaluated cell viability following 24 h NP exposure with the CellTiter GLO® assay. In Fig. 1, a general concentration-dependent decrease in ATP signal can be observed for every evaluated NP—cell type combination. Although the extent of this decrease clearly varies, the onset of this downward trend depended on both the applied NP and the cell type. In all cell types, the most severe effect was observed following AuNP treatment, while the cells were least affected by the IONPs. The toxicity observed for the AgNPs can likely in part be explained in terms of Ag+-ion leaching [34]. In turn, the severe acute cytotoxicity induced by the AuNPs could possibly be attributed to genotoxicity due to direct interactions between the 3.8 nm diameter AuNPs and DNA [35]. In addition, note that determining NP concentrations is not straightforward, as various methods/models need to be applied for different NP materials (Additional file 1). This may affect the comparison of absolute concentrations of NPs of different materials and may additionally explain the severe toxicity observed here for the AuNPs. Given the limited loss of cell viability observed for the IONPs, the latter were selected for further evaluation of sublethal effects.Fig. 1

View Article: PubMed Central - PubMed

ABSTRACT

Background: While nanotechnology is advancing rapidly, nanosafety tends to lag behind since general mechanistic insights into cell-nanoparticle (NP) interactions remain rare. To tackle this issue, standardization of nanosafety assessment is imperative. In this regard, we believe that the cell type selection should not be overlooked since the applicability of cell lines could be questioned given their altered phenotype. Hence, we evaluated the impact of the cell type on in vitro nanosafety evaluations in a human and murine neuroblastoma cell line, neural progenitor cell line and in neural stem cells. Acute toxicity was evaluated for gold, silver and iron oxide (IO)NPs, and the latter were additionally subjected to a multiparametric analysis to assess sublethal effects.

Results: The stem cells and murine neuroblastoma cell line respectively showed most and least acute cytotoxicity. Using high content imaging, we observed cell type- and species-specific responses to the IONPs on the level of reactive oxygen species production, calcium homeostasis, mitochondrial integrity and cell morphology, indicating that cellular homeostasis is impaired in distinct ways.

Conclusions: Our data reveal cell type-specific toxicity profiles and demonstrate that a single cell line or toxicity end point will not provide sufficient information on in vitro nanosafety. We propose to identify a set of standard cell lines for screening purposes and to select cell types for detailed nanosafety studies based on the intended application and/or expected exposure.

Electronic supplementary material: The online version of this article (doi:10.1186/s12951-016-0220-y) contains supplementary material, which is available to authorized users.

No MeSH data available.