Studies on the biocompatibility and the interaction of silver nanoparticles with human mesenchymal stem cells (hMSCs)

Purpose Silver nanoparticles (Ag-NPs) are widely used in different areas, e.g., in the food, electronic, or clothing industry due to well-known slow-release antiseptic activities. Despite the widespread use of nanosilver, there is a serious lack of information concerning the biological activities of nanosilver on human tissue cells. Materials and methods In this study, the influence of spherical Ag-NPs (diameter about 100 nm) on the biological functions (proliferation, cytokine release, and chemotaxis) of human mesenchymal stem cells (hMSCs) was analyzed. Results The results showed a concentration-dependent activation of hMSCs at nanosilver levels of 2.5 μg mL −1 , and cytotoxic cell reactions occurred at Ag-NPs concentrations above 5 μg mL −1 . Cell proliferation and the chemotaxis of hMSC both decreased with increasing Ag-NPs concentrations. Different effects on the cytokine release from hMSCs were observed in the presence of Ag-NPs and Ag + ions. The release of IL-8 was significantly increased at high but noncytotoxic concentrations of Ag-NPs (2.5 μg mL −1 ). In contrast, the levels of IL-6 and VEGF were concomitantly decreased compared to the control group. The synthesis of IL-11 was not affected at different Ag-NP concentrations. The agglomeration tendency of Ag-NPs in different biological media increased with a high electrolyte content, e.g., in RPMI. However, complexation with fetal calf serum in the cell culture media stabilized the Ag-NPs against agglomeration. Conclusion In summary, the results showed that Ag-NPs exert cytotoxic effects on hMSCs at high concentrations but also induce cell activation (as analyzed by the release of IL-8) at high but nontoxic concentrations of nanosilver.