The morphology of nZnO (A) and bZnO (B) particles by TEM and their translocation into the skin after topical application. TEM images of nZnO and bZnO materials reveal the differences in particle size and morphology. Scale bar 50 nm. Hyperspectral image analysis of PBS (C), nZnO (D), bZnO (E), OVA/SEB sensitized (F), OVA/SEB and nZnO treated (G), and OVA/SEB and bZnO treated (H) skin sites. Images are shown at 40x magnification, insets refer to the presence of particles in the skin or on its surface.