Effects of gold and silver nanoparticles in cultured human osteoarthritic chondrocytes

Abstract

The aim of our study was to evaluate the effects of gold (Au) and silver (Ag) nanoparticles (NPs) at different concentrations on cultured human osteoarthritic chondrocytes. Cell viability and inducible nitric oxide synthase expression were evaluated by light microscopy. Using transmission electron microscopy (TEM) and field emission gun-based scanning transmission electron microscopy/energy dispersive spectroscopy (FEG-STEM/EDS) allowed us to localize NPs. Gene expression of matrix metalloproteinases 1, 3 and 13 and A disintegrin and metalloproteinase with thrombospondin motifs -4 and -5 were carried out by real-time polymerase chain reaction. A cell viability test indicated a significant dose-dependent cytotoxic effect of both NPs. At concentrations of 160 and 250 μM NP light microscopy showed chondrocytes with signs of apoptosis and an increased presence of inducible nitric oxide synthase. Au-NPs were characterized by FEG-STEM/EDS and TEM analysis localized NPs in cytoplasm and in endocytotic vesicles. On the contrary, the Ag-NPs were undetectable by FEG-STEM/EDS and TEM. Increased gene expression, particularly in matrix metalloproteinase-3, was observed for both NPs (160 μM), but at a concentration of 250 μM the expression of the evaluated genes became lower. Our in vitro studies, although preliminary, suggest that engineered Au and Ag-NPs appear to be harmful for human osteoarthritic chondrocytes in high concentrations (160-250 μM).

Unaffected features of BSA stabilized Ag nanoparticles after storage and reconstitution in biological relevant media

“…On this regard, the little amount of BSA stabilized Ag-NP needed to reach bactericidal effect is a great advantage to minimize any other toxic effect. In fact, the nanomolar level reached with Ag-NP/BSA2 is much lower than the cytotoxic dose determined in vitro on osteoblasts, osteoclasts and osteoarthritic chondrocytes [10,11]. Hence, the application of Ag-NP/BSA2 to medical implants may be nonhazardous to human health.…”

“…Therefore, BSA stabilized Ag-NP are indeed extremely efficient as antimicrobial agents. In vitro cytotoxicity studies showed that 65 nm Ag-NP appeared to be harmful for human osteoarthritic chondrocytes only at high concentrations (160-250 M) [10]. On the contrary, antibacterial effects of polyvinylpyrrolidone (PVP) stabilized Ag-NP against S. epidermidis occurred at higher concentrations than those inducing cytotoxicity in primary osteoblasts and osteoclasts [11].…”

“…Considering that human exposure to foreign materials inevitable raises concerns on new health risks, Ag-NP have been also the subject of extensive nanotoxicology studies using in vivo and in vitro experiments [10][11][12]. The outcome is still limited and somewhat contradictory, especially because the size, shape and surface properties of Ag-NP strongly affect the antimicrobial activity versus cytotoxicity response [13].…”

“…In addition, the toxic concentration varies greatly from different mammalian cells as well as the inhibitory concentration changes for different bacteria strains. In general, a significant dose-dependent effect has been observed; clearly indicating that high efficacy at the lowest possible concentration is a major requirement of antimicrobial NP-Ag to be used in orthopedic related biomaterials [10,11] Due to the large positive reduction potential of Ag + ions, Ag-NP oxidation is thermodynamically unfavorable resulting in quite stable aqueous suspensions without the aid of capping ligands. However, biological relevant media strongly induce Ag-NP aggregation due to the high ionic strength that reduces the electrical double layer around the NP [14].…”

In Vitro Effect of Gold or Silver Nanoparticles on Meiotic and Postmeiotic Fractions of Rat Germinal Cells

“…Analysing the ultrastructure, no particular cell morphological damage seems to occur in the cells of both fractions. The behaviour of Ag-NPs, that were undetectable in all observed samples by FEG-STEM/EDS or TEM, was different, as we had already observed in human spermatozoa [16] and in osteoarthritis chondrocytes [23]. In that case, we hypothesised that the high concentration of Ag-NPs could increase the release of Ag+ ions [24] that may easily penetrate into the cells and interfere with the cell structures.…”