Uptake and intracellular distribution of silver nanoparticles in human mesenchymal stem cells.
Silver nanoparticles (Ag-NP) are widely used due to their well-known antibacterial effects. In medicine Ag-NP have found applications as wound dressings, surgical instruments and bone substitute biomaterials, e.g. silver-containing calcium phosphate cements. Depending on the coating technique, during resorption of a biomaterial Ag-NP may come into close contact with body tissues, including human mesenchymal stem cells (hMSC). Despite the widespread uses of Ag-NP, there is a serious lack of information concerning their biological effects on human cells. In this study the uptake of Ag-NP into hMSC has been analyzed and the intracellular distribution of Ag-NP after exposure determined. Non-agglomerated (dispersed) Ag-NP from the cell culture medium were detected as agglomerates of nanoparticles within the hMSC by combined focused ion beam/scanning electron microscopy. The silver agglomerates were typically located in the perinuclear region, as determined by light microscopy. Specific staining of cellular structures (endo-lysosomes, nuclei, Golgi complex and endoplasmatic reticulum) using fluorescent probes showed that the silver nanoparticles occurred mainly within endo-lysosomal structures, not in the cell nucleus, endoplasmic reticulum or Golgi complex. Quantitative determination of the uptake of Ag-NP by flow cytometry (scattergram analysis) revealed a concentration-dependent uptake of the particles which was significantly inhibited by chlorpromazine and wortmannin but not by nystatin, indicating clathrin-dependent endocytosis and macropinocytosis as the primary uptake mechanisms.
Greulich
C
C
Bergmannsheil University Hospital/Surgical Research, Ruhr University Bochum, Germany. christina.greulich@rub.de
Diendorf
J
J
Simon
T
T
Eggeler
G
G
Epple
M
M
Köller
M
M
D004705:Endocytosis; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D011205:Povidone / Q000737:chemistry; D012834:Silver / Q000378:metabolism*
D012834:Silver; D011205:Povidone