Figure 2.

Agarose gel electrophoresis. (A) siRNA were complexed with PEI-Fe₃O₄ at different Fe:siRNA (w/w) ratios. (B) siRNA release assayed by heparin decomplexation. Various w/w ratios of heparin to siRNA were added, and the mixtures were further incubated for 30 min. (C) Effect of the different incubation times on serum stability of siRNA. siRNA (0.5 µg/sample), either in naked form or complexed with PEI-Fe₃O₄, was mixed with fresh fetal bovine serum (1:1, v/v) to achieve a 50% serum concentration, and was incubated at 37°C for various periods of time. N represents naked siRNA, while C represents PEI-Fe₃O₄/siRNA complexes. PEI-Fe₃O₄, polyethyleneimine-functionalized magnetic iron oxide; siRNA, small interfering RNA.