Figure 7. In vitro and In vivo gene delivery assay by using GE11 peptide as the targeting element. A) Transfection efficiencies of various PEI, ePEI, or gPEI polyplexes in SMMC-7721 cells at N/P ratios of 10:1. In the blocking assay, 0.5 mM free peptide GE11 was coincubated with the polyplexes. Results are shown as relative light units (RLU)/mg protein. One microgram plasmid DNA per well was used. B) In vivo gene delivery of DNA polyplexes. 50 µg pGL3 plasmid DNA was condensed with PEI, ePEI, or gPEI at N/P ratio (10:1). The DNA polyplexes were injected intravenously into SMMC-7721 tumor-bearing mice. Luciferase activities were measured after 24 h. In the competitive assay, 100 µg free peptide GE11 was coinjected with the gPEI/DNA polyplexes. Data are shown as mean ±SD (n=5).