Figure 4.

(a) MTT assay (percent cell survival) of cells treated with polymer only or polyplexes formulated at N/P ratios of 5 or 10. Samples were analyzed 48 h post-transfection. (b) The percent of cells whose membranes are intact and not permeable to propidium iodide stain as determined via flow cytometry. Cells were treated with polymer only or polyplexes at N/P ratios of 5 and 10. Samples were analyzed 4 h post-transfection. All data are standardized to cells only, and control and error bars are the standard deviation of three replicates.