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. 2012 Jul 18;116(34):18440–18450. doi: 10.1021/jp303267y

Figure 5.

Figure 5

Cationic lipid is associated with internalized siRNA in LNP siRNA systems. The amount of external cationic lipid in LNP siRNA systems was assayed as a function of the siRNA phosphate-to-cationic lipid charge ratio using the FRET lipid mixing assay described in the Experimental Section. Three LNP systems DLinKC2-DMA/DSPC/Chol/PEG-lipid (40/11.5/47.5/1; mol/mol) were prepared at charge ratios of 0 (solid line), 0.25 (dotted line), and 1 (dash line). The lipid mixing assay was performed at pH 5.5 to ensure that essentially all external DLinKC2-DMA was positively charged. The reaction was initiated by injecting the LNP (at t = 30 s) into a stirred cuvette containing the anionic DOPS/NBD-PE/Rh-PE (98:1:1 molar ratio) vesicles.