Fig. 3. PSNA characterization. (a) Particle size distributions of PSNAs measured by Nanoparticle Tracking Analysis. (b) Sequence-specific labelling of external corona by hybridization to a complementary oligonucleotide. PSNAs and non-DNA-functionalized PMPC25–PDPA72 polymersome controls were challenged with FAM-labelled oligonucleotides complementary (Comp) and non-complementary (Ncomp) to the oligonucleotides in the PSNA corona. Unbound DNA was removed by ultrafiltration. Highest loading is achieved by the PSNA sample for which the labelled oligo is complementary to the corona. Data are presented as mean and SD (n = 3). Samples were compared using unpaired two-tailed t-tests **p < 0.01. (c) and (d) Representative transmission electron micrographs of PSNAs positively stained with 0.75% phosphotungstic acid solution adjusted to pH 7.4 to prevent PSNA disassembly. Left, magnified view of the grid. Scale bars: 1 μm (c); 200 nm (d).
