This video shows techniques for labeling of human embryonic stem cells and mesenchymal stem cells with fluorescent dyes. This technique can be used for an in vivo tracking of transplanted stem cells with optical imaging and for histopathological correlations with fluorescence microscopy.
A subscription to JoVE is required to view this content. Sign in or start your free trial.
Method Article
Labeling Stem Cells with Fluorescent Dyes for non-invasive Detection with Optical Imaging
In This Article
Summary
Abstract
Optical imaging (OI) is an easy, fast and inexpensive tool for in vivo monitoring of new stem cell based therapies. The technique is based on ex vivo labeling of stem cells with a fluorescent dye, subsequent intravenous injection of the labeled cells and visualization of their accumulation in specific target organs or pathologies. The presented technique demonstrates how we label human mesenchymal stem cells (hMSC) by simple incubation with the lipophilic fluorescent dye DiD (C67H103CIN2O3S) and how we label human embryonic stem cells (hESC) with the FDA approved fluorescent dye Indocyanine Green (ICG). The uptake mechanism is via adherence and diffusion of the lypophilic dye across the phospholipid cell membrane bilayer. The labeling efficiency is usually improved if the cells are incubated with the dye in serum-free media as opposed to incubation in serum-containing media. Furthermore, the addition of the transfection agent Protamine Sulfate significantly improves contrast agent uptake.
Protocol
Labeling of mesenchymal stem cells with the fluorescent dye DiD
- To begin the procedure for labeling mesenchymal stem cells, trypsinize and count the cells to get a suspension with a defined number of cells.
- Take the cells out of the incubator and aspirate out old media from the flasks containing the cells to be labeled
- Wash the cells with 10 ml of Mg/Ca-free PBS. Aspirate out the PBS. The Mg and Ca would inhibit the Trypsin, therefore we use PBS without these.
- Add pre-warmed 0.05% Trypsin, for a T75 flask we use 5ml. Ensure that the entire surface of the flask is covered.
- Incubate at 37°C in the incubator for about 5....
Access restricted. Please log in or start a trial to view this content.
Discussion
OI is a relatively new imaging technique, based on the detection of fluorescence. OI is as sensitive as radiotracer-based imaging techniques, but not associated with any irradiation exposure. OI provides an effective means of tracking cells non-invasively and repetitively, thereby providing insight into cell migration to the target site. One major limitation of the technique is the limited tissue penetration of fluorescent probes in vivo. Thus, a tracer accumulation in deep tissues, more than about 5-10 cm from the skin .......
Access restricted. Please log in or start a trial to view this content.
Acknowledgements
This project was supported by a Leon J. Thal SEED grant from the California Institute for Regenerative Medicine. Tobias Henning was funded by a Research stipend from the German Research Association (DFG, HE 4578/1-2). We want to gratefully acknowledge Juanito Meneses for his advice on the culture of human embryonic stem cells.
....Access restricted. Please log in or start a trial to view this content.
Materials
| Name | Company | Catalog Number | Comments | |
|---|---|---|---|---|
| Indocyanine Green (IR-125) | Reagent | Fisher Scientific | AC41254-1000 | |
| DMSO | Reagent | Sigma-Aldrich | D-2650 | |
| D-MEM High Glucose | Reagent | Sigma-Aldrich | D5648 | |
| Gelatin | Reagent | Sigma-Aldrich | G1890 | Dilute to final concentration of 0.1% in PBS |
| PBS, Mg and Ca free | Reagent | GIBCO, by Life Technologies | 14190-144 | |
| Trypsin-EDTA 0.05% | Reagent | Invitrogen | 25300-120 | |
| Trypsin-EDTA 0.25% | Reagent | Invitrogen | 25200-114 | |
| FCS, characterized | Reagent | Hyclone | SH30071.03 | |
| Cell Strainer (40 μm Nylon) | Reagent | BD Biosciences | 352340 | |
| DiD | Reagent | Molecular Probes, Life Technologies | V-22887 | |
| Knockout DMEM | Reagent | GIBCO, by Life Technologies | 10829018 | |
| Knockout Serum Replacer | Reagent | GIBCO, by Life Technologies | 10828028 | |
| b-Mercapt–thanol | Reagent | Sigma-Aldrich | 7522 | |
| Non-essential Amino Acids | Reagent | GIBCO, by Life Technologies | 11140050 | |
| FGF-2 | Reagent | R&D Systems | 233-FB-025 | |
| Glutamine 200mM | Reagent | GIBCO, by Life Technologies | 25030081 | |
| Penicillin/Streptomycin | Reagent | GIBCO, by Life Technologies | 15140-122 | |
| Protamine Sulfate | Reagent | American Pharmaceutical Partners |
References
- Daldrup-Link, H. E., Rudelius, M., Metz, S., Piontek, G., Settles, M., Pichler, B., Heinzmann, U., Weinmann, H. J., Schlegel, J., Link, T. M., Rummeny, E. J., Oostendorp, R. A. J. Stem cell tracking with Gadophrin-2 -- a bifunctional contrast agent for MR imaging, optical imaging and fluorescence microscopy. Eur J Nucl Med Mol Imaging. 31, 1312-1321 (2004).
- Simon, G. H., Daldrup-Link, H. ....
Access restricted. Please log in or start a trial to view this content.
Reprints and Permissions
