title: Studies on the biocompatibility and the interaction of silver nanoparticles with human mesenchymal stem cells (hMSCs).
abstract: OBJECTIVE
  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.
  
  
  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 microg mL(-1), and cytotoxic cell reactions occurred at Ag-NPs concentrations above 5 microg 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 microg 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Surgery, Surgical Research, Berufsgenossenschaftliches Universitätsklinikum Bergmannsheil GmbH, Bürkle-de-la-Camp-Platz 1, 44789, Bochum, Germany. christina.greulich@rub.de
authors.forename: C
authors.initials: C
authors.lastname: Greulich
authors.forename: S
authors.initials: S
authors.lastname: Kittler
authors.forename: M
authors.initials: M
authors.lastname: Epple
authors.forename: G
authors.initials: G
authors.lastname: Muhr
authors.forename: M
authors.initials: M
authors.lastname: Köller
mesh_terms: D049109:Cell Proliferation; D002633:Chemotaxis; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D017370:Interleukin-11 / Q000096:biosynthesis; D015850:Interleukin-6 / Q000096:biosynthesis; D016209:Interleukin-8 / Q000096:biosynthesis; D059630:Mesenchymal Stem Cells / Q000187:drug effects* / Q000378:metabolism; D053758:Nanoparticles / Q000737:chemistry*; D012834:Silver / Q000737:chemistry* / Q000494:pharmacology; D018709:Statistics, Nonparametric
chemical_list: D017370:Interleukin-11; D015850:Interleukin-6; D016209:Interleukin-8; D012834:Silver