Figure 5: The gene delivery efficiencies of PEI600, PEI-β-CyD, CY11-PEI-β-CyD, and PEI25KDa with different N/P ratios in (a) COS-7, (b) HepG2, and (c) PC-3 cells. PEI25KDa at an N/P ratio of 10 shows the highest gene delivery efficiency. Data were shown as mean ± SD, (* as compared with other samples in the same group). The green fluorescence emitted by green proteins expressed after the transfer of CY11-PEI-β-CyD/pEGFP at an N/P ratio of 25 to cells: (d) COS-7, (e) HepG2, and (f) PC-3 cells. A fluorescence microscope is used. Fluorescence is more evident in COS-7 (FGFR-positive) and HepG2 (FGFR-positive) cells than in PC-3 (FGFR-negative) ones.