Figure 7.

Analysis of the presence of chitosan in the nucleus of cells positive for transgene expression of green fluorescent protein (GFP). (a,b) At early time points (between 18 and 26 hours) of transfection, GFP-positive (green) cells were analyzed for the presence of rhodamine B isothiocyanate-chitosan (red) in the nucleus, where the nucleus was distinguished by a reduced intensity of GFP and by disseminated intravascular coagulation (bottom left quadrant). (a) A cell representative of the vast majority of GFP-expressing cells with no intranuclear chitosan. (b) The zoomed image of the nucleus of the cell in a showing an absence of chitosan. (c) At 48 hours, a small fraction of cells (~2–5%) show some chitosan inside the nucleus, delineated here by a white border to increase contrast. Arrowheads indicate polyplexes on the edge of the nucleus, as seen in most transfected cells.