Transport of Metal Oxide Nanoparticles Across Calu-3 Cell Monolayers Modelling the Air-Blood Barrier

As inhalation is the major exposure route for nanoparticles, the question if inhaled particles can overcome the respiratory epithelial barrier and hence enter the body is of great interest. Here, we adapted the for soluble substances well established Calu-3 in vitro air-blood barrier model to the use of nanoparticle transport testing. As the usually used filter supports hindered particle transport due to their small pore size, supports with a pore size of 3 μm had to be used. On those filters, barrier and transport characteristics of the cells were tested and culture conditions changed to obtain optimal conditions. Functionality was confirmed with transport experiments with polystyrene model particles prior to testing of industrially relevant engineered metal oxide particles. Except for CeO2 nanoparticles, no transport across the epithelial barrier model could be detected. Paracellular permeability and barrier function was not affected by any of the nanoparticles, except for ZrO2.