These cells are generated by chemical transfection of CdSe/ZnS nanoparticles, 100 nm in diameter and show a strong fluorescent signal (Excitation maximum= 515 nm; Emission maximum= 520-550 nm) detectable by standard FITC filters. These cell retain GFNP labeling through 3+ passages and can be differentiation into chondrogenic, adipogenic or osteogenic lineages. Excellent for regeneration, toxicity and related studies.

1. Introducing: Green Fluorescent Nanoparticle-labeled human Mesenchymal Stem Cells
These cells add to our fluorescein, rhodamine and GFP-expressing MSCs and offer
an alternative fluorescent MSCs with the following properties:
•Generated by chemical transfection of CdSe/ZnS nanoparticles, 100 nm in
diameter
•Strong fluorescent signal (Exmax= 515 nm; Emissionmax= 520-550 nm)
detectable by standard FITC filters.
•Retains fluorescence through growth or differentiation into chondrogenic,
adipogenic or osteogenic lineages.
•Possible indicator of endoplasmic processing within MSCs
•Fluorescence is detectable in three successive passages and diminishes with
passage.
•Useful in tracking and imaging investigations based on MSCs

2. FITC analysis of cells during second passage following transfection. Image obtaining using FITC
filter on Olympus CKX41 microscope at 200 X equipped with a Retiga 2000 digital camera and
Q-Capture software program. Scale bar is 25 micrometers.

3. FITC analysis of cells during third passage following transfection. Image obtaining using FITC
filter on Olympus CKX41 microscope at 200 X equipped with a Retiga 2000 digital camera and Q-
Capture software program. Scale bar is 25 micrometers. Note that this culture is at higher cell
density than the previous image.

4. FITC analysis of cells during fourth passage following transfection. Image obtaining using FITC
filter on Olympus CKX41 microscope at 200 X equipped with a Retiga 2000 digital camera and Q-
Capture software program. Scale bar is 25 micrometers. Fluorescent nanoparticles are less
prevalent within the cytoplasm than earlier passages.

5. Osteogenic differentiation of Grn-fluorescent nanoparticle-labeled MSCs. Image obtaining using phase
contrast Olympus CKX41 microscope at 100 X equipped with a Retiga 2000 digital camera and Q-Capture
Pro software program. Scale bar is 25 micrometers. Note the presence of mineral deposits indicating
differentiation into osteoblasts. Chondrogenic and adipogenic differentiation was also apparent .