Figure 2: Optimization of CD133+ transfection with different compositions of miR/PEI complexes. Cells were transfected with Cy3-labeled complexes consisting of four different miR amounts (10, 20, 30, and 40 pmol) and three different N/P ratios (2.5, 5, and 7.5). Uptake efficiency (a) and cytotoxicity (b) were measured 18 h after transfection by flow cytometry. Untransfected cells were used as control. Values are presented as mean ± SEM; ; statistic was performed versus 10 pmol miR with respective N/P ratio (a) and versus control (b); ; ; .