A novel exposure system termed NAVETTA for in vitro laminar flow electrodeposition of nanoaerosol and evaluation of immune effects in human lung reporter cells

A new prototype air-liquid interface (ALI) exposure system, a flatbed aerosol exposure chamber termed NAVETTA, was developed to investigate deposition of engineered nanoparticles (NPs) on cultured human lung A549 cells directly from the gas phase. This device mimics human lung cell exposure to NPs due to a low horizontal gas flow combined with cells exposed at the ALI. Electrostatic field assistance is applied to improve NP deposition efficiency. As proof-of-principle, cell viability and immune responses after short-term exposure to nanocopper oxide (CuO)-aerosol were determined. We found that, due to the laminar aerosol flow and a specific orientation of inverted transwells, much higher deposition rates were obtained compared to the normal ALI setup. Cellular responses were monitored with postexposure incubation in submerged conditions, revealing CuO dissolution in a concentration-dependent manner. Cytotoxicity was the result of ionic and nonionic Cu fractions. Using the optimized inverted ALI/postincubation procedure, pro-inflammatory immune responses, in terms of interleukin (IL)-8 promoter and nuclear factor kappa B (NFκB) activity, were observed within short time, i.e. One hour exposure to ALI-deposited CuO-NPs and 2.5 h postincubation. NAVETTA is a novel option for mimicking human lung cell exposure to NPs, complementing existing ALI systems.