Table 1. Effect of PLL block length and modifying siRNA with 3’-cholesterol on the minimum N/P ratio required to form neutral / electropositive polyplexes of siRNA with PLL-PEG(5K).

siRNA (siCtrl: 5’- UGG UUU ACA UGU CGA CUA A - 3’ with 3’-UU overhangs) or Chol-siRNA (siCtrl modified with 3’-cholesterol on the sense strand) was mixed with PLL-PEG(5K) in 0.1 M HEPES [pH 7.4] over a range of N/P ratios, incubated at room temperature for 30 min, then run on a 1X TBE agarose/SYBR Green II gel. The first N/P ratio where polyplexes were completely retained in the well was defined as the minimum N/P ratio required for complexation. All N/P ratios are representative of two independent experiments.

	siRNA		Chol-siRNA
Polymer	N/P ratio	Loading (wt%)	N/P Ratio	Loading (wt%)
PLL10-PEG(5K)	7	(6.2)	4	(10.4)
PLL30-PEG(5K)	6	(13.3)	3	(23.5)
pLL50-PEG(5K)	5	(18.8)	2	(36.6)