Figure 7.
Serum stability of unmodified si-2 and 2′-modified si-2OMe and si-2 F. Different siRNAs were incubated in 10% FBS, 100% mouse serum, or 100% human serum at 37°C and withdrawn at the indicated time points. Samples were separated by 15% polyacrylamide-TBE under non-denaturing conditions and visualized by staining with GelRedTM Nucleic Acid Gel Stain. The 2′-modified si-2OMe and si-2 F were still detectable at 48 h of incubation, indicating dramatically enhanced levels of serum stability compared with the unmodified si-2. Three independent experiments were performed.