title: Quantum dots do not affect the behaviour of mouse embryonic stem cells and kidney stem cells and are suitable for short-term tracking.
abstract: Quantum dots (QDs) are small nanocrystals widely used for labelling cells in order to enable cell tracking in complex environments in vitro, ex vivo and in vivo. They present many advantages over traditional fluorescent markers as they are resistant to photobleaching and have narrow emission spectra. Although QDs have been used effectively in cell tracking applications, their suitability has been questioned by reports showing they can affect stem cell behaviour and can be transferred to neighbouring cells. Using a variety of cellular and molecular biology techniques, we have investigated the effect of QDs on the proliferation and differentiation potential of two stem cell types: mouse embryonic stem cells and tissue-specific stem cells derived from mouse kidney. We have also tested if QDs released from living or dead cells can be taken up by neighbouring cells, and we have determined if QDs affect the degree of cell-cell fusion; this information is critical in order to assess the suitability of QDs for stem cell tracking. We show here that QDs have no effect on the viability, proliferation or differentiation potential of the two stem cell types. Furthermore, we show that the extent of transfer of QDs to neighbouring cells is <4%, and that QDs do not increase the degree of cell-cell fusion. However, although the QDs have a high labelling efficiency (>85%), they are rapidly depleted from both stem cell populations. Taken together, our results suggest that QDs are effective cell labelling probes that are suitable for short-term stem cell tracking.
authors.affiliation: Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom. a.rakraszewska@googlemail.com
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Rak-Raszewska
authors.forename: Marco
authors.initials: M
authors.lastname: Marcello
authors.forename: Simon
authors.initials: S
authors.lastname: Kenny
authors.forename: David
authors.initials: D
authors.lastname: Edgar
authors.forename: Violaine
authors.initials: V
authors.lastname: Sée
authors.forename: Patricia
authors.initials: P
authors.lastname: Murray
mesh_terms: D000818:Animals; D001692:Biological Transport; D016923:Cell Death / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D058948:Cell Tracking / Q000009:adverse effects* / Q000379:methods*; D018920:Coculture Techniques; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism / Q000637:transplantation; D007668:Kidney / Q000166:cytology*; D051379:Mice; D045663:Quantum Dots; D013194:Staining and Labeling; D033581:Stem Cell Transplantation; D013997:Time Factors