Labeling and Imaging of Human Mesenchymal Stem Cells with Quantum Dot Bioconjugates during Proliferation and Osteogenic Differentiation in Long Term

Keywords:
quantum dots, mesenchymal stem cell, cell labeling

Abstract:
Tissue engineering approaches have the potential to repair damaged bone using a patient’s own mesenchymal stem cells (hMSCs). The objective of this study was to determine the feasibility of long-term labeling of hMSCS with semiconductor quantum dot (QD) conjugates under proliferative and osteogenic differentiation. Cadmium selenide QDs were conjugated to RGD peptide. Optimal concentrations and labeling time to conjugate the QDs with hMSCs were first determined as 30 nM and overnight incubation. Human MSCs were then either kept in control medium to test cytotoxicity or cultured in control medium with osteogenic supplements to test differentiation potential. Fluorescent microscopy was used to visualize QD-conjugated hMSCs up to 28 days. DNA content was quantified to determine proliferation. Fluorescent microscopy showed that the QDs remained attached to the cells at all time points under all conditions. Quantitatively, DNA content showed a slight but non-significant decrease in cells labeled with QDs as compared to controls without QDs. This study shows the feasibility of using QDs for longterm tracking in hMSCs experiments and may be applicable to future in vitro and in vivo studies.

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Nanotech 2005 Conference Program Abstract