Figure 4.
Preservation of the morphologies of PEG-b-PPA/DNA micelles by reversible disulfide crosslinking and shape-dependent gene transfection efficiency in vivo. (a–d) TEM images of the crosslinked micelles initially obtained in 7:3 (v/v) (a), 5:5 (b), 4:6 (c), and 1:9 DMF–water mixtures (d). All scale bars represent 200 nm. (e) The average lengths and diameters of crosslinked micelles as shown in (a) through (d). Plot shows mean ± standard deviation (n > 100, *p < 0.01; Student’s t-test). (f) Average zeta potentials of the micelles in water and isotonic sodium chloride solution. Plot shows mean ± standard deviation (n = 3). (g) Distribution of luciferase expression at 4 h after intrabiliary infusion of PEG-b-PPA/DNA micelles with spherical (a), rod-like (b), and worm-like (d) shapes, characterized with in vivo bioluminescence imaging. The control group is a benchmark expression level obtained by the hydrodynamic infusion of plasmid DNA (See Supporting Information). (h) Quantitative comparison of luciferase expression in rat liver at 4 h after infusion for the same set of micelles. Plot shows mean ± standard deviation (n = 3). Background reading for this assay was 3.5 × 102 total photon counts per second.