*2.10. Gel Retardation Assay*

One microgram of siRNAs was mixed with cationic liposomes at various charge ratios (+:−) from 1:1 to 4:1. After 15 min incubation of the siRNA lipoplexes, they were analyzed by 18% acrylamide gel electrophoresis for siRNA in Tris-Borate-EDTA buffer (pH 8.0) and detected by ethidium bromide staining, as reported previously [30].
