Figure 1.

Optimization of PEI/pGFP polyplex formulation. (a-c) Degree of condensation (complexation) analyzed by SyBr Green dye exclusion assay (a), size (left y-axis) and polydispersity index (PDI, right y-axis) (b), and net surface charge (zeta potential) (c) of the polyplexes of PEI/pGFP at indicated weight ratio on each graph. (d) Size (left y-axis) and PDI (right y-axis) of polyplex of PEI/pGFP prepared at weight ratio of 2 within different environment. Polyplexes were either originally prepared in 1.3 ml of pure “Water”, “PBS”, or “HBS”, respectively, or first prepared in 100 μl of pure water and diluted (to final volume of 1.3 ml) using water or indicated buffers for “Water/Water”, “Water/PBS, or “Water/HBS” samples, respectively. Results are presented as mean ± SD (n = 3).