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. 2018 Mar 7;6(1):17–32. doi: 10.1016/j.jcmgh.2018.02.013

Figure 2.

Figure 2

Characterization of the targeted polyplex. (A) Hydrodynamic size of both targeted (Ga-PEG-PLL) and untargeted (PEG-PLL) polyplex measured by dynamic light scattering technique. The targeted polyplex was synthesized from Ga-PEG5K-PLL27 and the untargeted version from PEG5K-PLL30 block copolymer by complexing with gastrin siRNA at the N/P ratio of 5. Attachment of the targeting ligand, Ga-10, on the targeted polyplex surface did not change the polyplex size significantly. (B) A series of untargeted PEG-PLL polyplex formulations from varied PEG (5k–20k) and PLL block lengths (30–100 lysine units) encapsulating gastrin siRNA (19 bp) at the N/P ratio of 5 showed remarkable enhancement in serum stability compared with free siRNA. No siRNA degradation was observed for at least 7 hours in 90% fresh human serum. PEG5K-PLL30 was chosen as an untargeted polyplex for all in vitro and in vivo investigations. (C) Unencapsulated (free) siRNA degrades very fast in human serum (serum half-life, <10 min).