Deposition Efficiency of Fluorescent Polystyrene Particles on Human Airway Epithelial Cells in a Novel Live Cell Exposure Chamber
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Ambient air pollution is a leading risk factor for premature mortality and morbidity arising from increased pulmonary and cardiac pathogenesis. The composition of ambient air pollution is highly dependent on local atmospheric accumulation of primary and secondary pollutants, including particulate matter (PM), ozone, and others. Airborne PM is a known driver of adverse health outcomes associated with exacerbations of asthma and cardiopulmonary disease through mechanism(s) that remain poorly understood. Recent advances in air-liquid-interface (ALI) techniques, for the culture of primary human airway epithelial cells (pHAEC), have allowed for in vitro investigation of particulate deposition in the human airway. Exposing pHAEC cultured under ALI conditions to particulates is often challenging and is usually accomplished by exposing cells to a suspension of extracted particles. However, this technique compromises the integrity of the ALI culture and may result in off target effects. Therefore, the objective of this work was to develop a more physiologically relevant exposure model for the deposition of particles on pHAEC cultured under ALI conditions. Our approach utilizes the high spatiotemporal resolution afforded by fluorescence confocal microscopy, which allows for direct visualization of particle deposition on pHAEC in a novel ALI exposure chamber that provides physiologic pH, temperature and humidity. Using this chamber, we measure the deposition efficiency of aerosolized fluorescent polystyrene particles on pHAEC maintained at ALI. Under conditions of negative flow (200 mL/min), normal pHAEC maintained at ALI were exposed to a dilute aerosol of 0.5 um fluorescent polystyrene particles for 10 min, resulting in approximately 0.1% particle deposition. In summary, our findings demonstrate that a particle deposition efficiency of 0.1% results in measurable coverage of the surface of pHAEC. Taken together, our results suggest that aerosolization of fluorescent particles, coupled with fluorescence confocal microscopy, is a suitable technique for modeling underlying mechanisms associated with particulate deposition in the human airway. This abstract of a proposed presentation does not necessarily reflect USEPA policy.