Fig. 6. SEM size distribution histograms (a) for all prepared NPs generated from manually measuring the size of NPs from SEM micrographs (n = 120 at least). The spherical shape of the NPs were confirmed using uncoated SEM images (b), and bright field TEM images (c) on carbon/formvar-coated 300-mesh grids. The increase in chitosan amount in the NP preparations was associated with more defined NPs structure on the edges of the NPs.