Figure 6.

Flow cytometry measurements showing the uptake of polyplexes made of Alexa Fluor 488-labeled siRNA and linear bisspermine and linear or dendritic tetraspermine compared to polyethylenimine (PEI). Mean fluorescence intensities were quantified in H1299/LUC cells after a 24 h incubation with polyplexes prepared at N/P ratios of 2 and 10. Trypan blue treatment was performed to quench the extracellular binding of siRNA polyplexes to the cell. Cells treated with trypan blue showed decreased mean fluorescence intensities.