Cellular Response to Delivery of Airborne Particles in Different Deposition Patterns through the Dosimetric Aerosol In Vitro Inhalation Device

SRIPRIYA NANNU SHANKAR, Amber O'Connor, Kiran Mital, Yuetong Zhang, Amin Shirkhani, Alex Theodore, Tara Sabo-Attwood, Stavros Amanatidis, Gregory S. Lewis, Arantzazu Eiguren-Fernandez, Otmar Schmid, Chang-Yu Wu, University of Florida

     Abstract Number: 706
     Working Group: Health-Related Aerosols

Abstract
Particle deposition in the respiratory tract occurs in different patterns depending on particle characteristics and an individual's respiratory mechanics. In this study, aerosolized CuO nanoparticles (CuONPs) were deposited in four patterns (spots, ring, slit, and circle) onto A549 cells cultured at the air-liquid interface via the Dosimetric Aerosol in Vitro Inhalation Device (DAVID), where the mass of CuONPs delivered was quantified by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). ImageJ analysis showed the deposition areas corresponding to spots, ring, rectangle, and circle patterns were ~10, 27, 7 and 68% of the cell culture insert’s area, respectively. The “global dose” was calculated as the mass of CuONPs delivered over the surface area of the cell culture insert, while the “regional dose” was calculated as the mass of CuONPs delivered over areas corresponding to the deposition patterns. Assessment of cell viability by alamarBlue assay showed there was no significant difference between spots-ring (p=0.9985), spots-circle (p=0.1522) and ring-circle (p=0.2042) at a global dose of 10 µg/cm², and there was no statistical difference (p>0.05) between any of the patterns at global dose of 20 µg/cm². The variation in cell viability with respect to the regional dose shows that the deposition area clearly had an influence in cellular response. The pattern wherein CuONPs were deposited in the least surface area was the slit (~7% of the total surface area of the insert), and this pattern had the highest impact on cell viability. The cell viability was lower for patterns with smaller deposition area, i.e., the cell viability increased in the order slit < spots < ring < circle. The results suggest potential cellular signaling, i.e., communication between cells in response to their environment. The study highlights the importance of considering deposition pattern and comparison of regional and global doses in in vitro inhalation toxicology.