Figure 5.
A comparison of in vitro gene transfection efficiencies of PEI25K (N/P = 10/1 and 30/1), PEG-NP, and HNPs by detecting the expression of a fluorescent protein GFP or Luc2 in SUM159 and MDA-MB-231 cells. HNPs loaded with the GFP or Luc2 expressing pDNA were prepared at a N/P ratio of 30/1, and the PEI25K/DNA complex was also prepared in the same way. The pDNA transfections were performed at a dose of 3 μg of the GFP or Luc2 expressing pDNA. Cells were incubated in the transfection solution for 48 h. (a) Representative images of GFP expression in cells transfected with the GFP expressing pDNA-loaded PEI25K or HNPs (100×). (b) The numbers of GFP expression cells per field of view (POV) counted under a fluorescent microscope. Results are from two independent experiments (n = 10), and five randomly selected fields were counted in each experiment. (c) The pDNA transfections were performed at a dose of 3 μg of Luc2 expressing pDNA and 30 ng of Renilla luciferase expressing pDNA. The activity of Luc2 in cells was determined using a dual luciferase reporter assay as described in the Experimental Section. Results are expressed as the relative luciferase reporter activity calculated as the ratio of firefly luciferase (Luc2) activity divided by the Renilla luciferase activity (mean ± SD, n = 3). *: p < 0.05, compared to the PEI25K (N/P = 10/1) and PEG-NP-transfected group.