Responses of RAW264.7 macrophages to water‐dispersible gold and silver nanoparticles stabilized by metal–carbon σ‐bonds

Abstract

Nanometals are currently receiving considerable attention for industrial and biomedical applications, but their potentially hazardous and toxic effects have not been extensively studied. This study evaluated the biological responses of novel water-dispersible gold (Au-NPs) and silver nanoparticles (Ag-NPs) stabilized by Au-C or Ag-C σ-bonds in cultured macrophages (RAW264.7), via analysis of the cell viability, the integrity of the plasma membrane, and the inflammatory and morphological properties. The cultured RAW264.7 was exposed to metal-NPs at various concentrations. The Ag-NPs showed cytotoxicity at high NP concentrations, but the cytotoxic effects of the Au-NPs were smaller than those of the Ag-NPs. For the microscopic analysis, both types of particles were internalized into cells, the morphological changes in the cells which manifested as an expansion of the vesicles' volume, were smaller for the Au-NPs compared with the Ag-NPs. For the Ag-NPs, the endocytosis abilities of the macrophages might have induced harmful effects, because of the expansion of the cell vesicles. Although an inflammatory response was observed for both the Au- and Ag-NPs, the harmful effects of the Au-NPs were smaller than those of the Ag-NPs, with minor morphological changes observed even after internalization of the NPs into the cells.

Selective inhibitory effects of 50-nm gold nanoparticles on mouse macrophage and spleen cells

“…Interestingly, gold in the form of colloid (Auranofin) was used for many years in the treatment of rheumatoid arthritis due to its ability to substantially decrease the inflammatory component of the disease (Madeira et al, 2012). AuNP show little cytotoxicity in vivo (Downs et al, 2012; Chen et al, 2013), but results in vitro have been mixed, with several studies indicating at least some immunostimulation (Du et alo., 2012; Liu et al, 2012) dependent on coating and stabilization (Hashimoto et al, 2014). Nevertheless, the feasibility of using AuNP for the inhibition of inflammatory diseases has been considered, even though the precise mechanisms relating gold with anti-inflammatory effects remain unclear (Sumbayev et al, 2013).…”

“…BioPure AuNP suspensions were added to the 1 ml cell cultures to give final concentrations of 0, 5, 25 and 50 μg AuNP/ml. These concentrations were based on previous in vitro studies (Hashimoto et al, 2014; Du et al, 2012) and two in vivo studies (Chen et al, 2013; Geiser et al, 2013), and ensured that these experiments were preformed well below overtly toxic dosages, so that immune effects could be measured in the absence of cell death. There were four replicate wells for each concentration in one half of the plate; the other half of the plate contained identical cultures with the addition of 1 μg LPS/mL ( Salmonella minnesota ,; Sigma, St. Louis, MO) in all wells to determine the effect of the AuNP on LPS-stimulated macrophages.…”

Silver Nanoparticle-Mediated Cellular Responses in Various Cell Lines: An in Vitro Model

“…The findings from this study suggest that the release of silver ions from the surface of small nanosilver particles is significantly higher in macrophages. When the macrophages were exposed to water-dispersible AgNPs, stabilized by Ag-C σ-bonds, toxicity was observed at higher concentrations (50–500 µg/mL) and cells exhibited vesicles with an expanded volume, membranolytic action, and inflammatory responses [59]. …”

Biomedical Nanoparticles: Overview of Their Surface Immune-Compatibility

“…A study by Hashimoto et al compared the exposure of cultured macrophages RAW264.7 to AuNPs with AgNPs. Although an inflammatory response was observed for both the Au-and Ag-NPs, the harmful cytotoxic effects of AuNPs were smaller than those of the Ag-NPs [78]. However, as described for other kinds of nanomaterials, the interaction between cells and Au nanoparticles could be mediated also by unspecific adsorption of serum proteins onto the gold surface [79].…”