Figure 7.

Intracellular distribution of plasmids in MSCs 4 hours posttransfection using Cy5 labeling. A MSCs were transfected by complexes of PEI600Da/pEGFP (N/P = 10), PEI₆₀₀-β-CyD/pEGFP (N/P = 30), and PEI25kDa/pEGFP (N/P = 10). The upper panel shows the merged photos (63) of plasmids labeled by Cy5 (green) at 649 nm excitation, lysosomes stained with LysoTracker red DND-99 dye (red), and nuclei stained with Hoechst 33342 (blue). The lower panel shows merged photos (63 × 3) taken by the same method as the upper panel. (B) Quantification of the percentage of cells with green plasmid signals in their lysosomes or nuclei in each group in the upper panel of (A). N, amount of nitrogen in PEI; P, amount of phosphate in 1 μg DNA.

Abbreviations: PEI₆₀₀-β-CyD, polyethylenimine₆₀₀-β-cyclodextrin; MSCs, mesenchymal stem cells; EGFP, enhanced green fluorescent protein.