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Critical Evaluation of Air-Liquid Interface Exposure Devices for In Vitro Assessment of Atmospheric Pollutants
Citation:
Zavala, J., A. Ledbetter, P. White, D. DeMarini, Ian Gilmour, AND M. Higuchi. Critical Evaluation of Air-Liquid Interface Exposure Devices for In Vitro Assessment of Atmospheric Pollutants. Environmental Mutagenesis and Genomics Society (EMGS), New Orleans, LA, September 26 - 30, 2015.
Impact/Purpose:
This project evaluates the ability of several air-liquid interface exposure devices to effectively permit exposure of mammalian cells to various atmospheres. This type of exposure is critical to understanding the health impacts of various atmospheres and atmospheric pollution on mammalian cells. This is part of the ACE project to evaluate a variety of polluted atmospheres for health effects.
Description:
Exposure of cells to atmospheric pollutants at the air-liquid interface (ALI) is a more realistic approach than exposures of attached cells submerged in liquid medium. However, there is still limited understanding of the ideal ALI device design features that permit reproducible assessments. We have compared several ALI devices for their ability to deliver both particles and gases to cells. The ALI devices tested use different mechanisms to deliver pollutants to the cells: diffusion, sedimentation, and electrostatic precipitation (ESP). For each device there are various experimental factors, such as the flow rate, flow conditioning, and pollutant characteristics that can adversely affect performance and, ultimately, the reliability and reproducibility of the observed effects. We used fluorescent polystyrene latex spheres as a surrogate for particulate matter to assess the ability of ALI devices to deposit particles. The particle loading in each well was determined by dissolving the spheres in ethyl acetate and measuring the fluorescence. Particles <100 nm rely on diffusion for deposition, whereas particles >1 µm rely on sedimentation. For particles in between, an external force, such as ESP is required for deposition. The interaction of ozone with an indigo dye on the surface of the well showed that diffusion alone permitted gas-cell interaction. Increasing the flow rate increased sensitivity of the diffusion devices to deliver gas to the cells. These results will be used to identify ALI devices that are most appropriate for particular exposure scenarios. [Abstract does not necessarily reflect the views or policies of the U.S. EPA.]