Fig. 1

Accumulation of NPs in keratinocytes and dermal fibroblasts. 500 nm polystyrene NPs were able to enter keratinocytes (a) and dermal fibroblasts (b). 100 nm polystyrene NPs also accumulated in keratinocytes (c) and fibroblasts (d)

The cryo-FIB image showed the possible location of intracellular NPs (a, scale bar: 20 μm). The particles in this location (b, scale bar: 5 μm) were identified by the XEDS to be high carbon (C) density particles which are different than the intracellular background with high level of oxygen (O) (c). CM: cell membrane. Resolution of XEDS is 75 nm x 75 nm