Fig. 1

Transwell chamber system that was used to culture and expose the A549 and MLE-12 CMLs. The displayed graphic shows the CMLs at the ALI (24 h after the apical medium was removed and the surface liquid was produced by the cells) and during/shortly after exposure using the ALICE, when the particles settle down and distribute between the individual compartments (surface liquid, cellular monolayer and basolateral medium). Insert surface area: 0.9 cm2. Membrane pore size: 3 μm