Fig. 3

Morphology of mRNA-loaded LPNs (a1, a2) and CS-PLGA NPs (b1, b2) visualized using SEM and TEM. a1, b1 SEM images show a smooth, spherical morphology of the mRNA-loaded nanoparticles and a2, b2 TEM images show the core–shell structure of the particles after staining with 0.5% (w/V) PTA