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Determining Real-Time Mass Deposition With a Quartz Crystal Microbalance in a Parallel-Flow, Electrostatic Air Liquid Interface Exposure System
KAMALJEET KAUR, Dana Overacker, Hamid Ghandehari, Chris Reilly, Robert Paine, Kerry Kelly, University of Utah
Abstract Number: 20
Working Group: Health-Related Aerosols
Abstract
Air-liquid interface (ALI) in vitro exposure systems are gaining interest as a more realistic strategy for in vitro particle exposure than submerged culture approaches. One of the persistent challenges in working with ALI systems is getting a good estimation of particle mass deposition, which defines the delivered dose to cells. Although a few commercially available ALI systems are equipped with online mass deposition monitoring, most studies use indirect methods to estimate mass doses. These different indirect methods may contribute to inconsistencies in the results from in vitro studies of aerosolized nanoparticles. This study explores the effectiveness of a commercially available Quartz Crystal Microbalance (QCM) system to estimate the real-time deposition of particle mass inside a parallel-flow, electrostatic ALI system. The QCM system required minor modifications including custom-designed and fabricated headers for the ALI chamber. Three QCM systems were simultaneously placed in three of the wells of a six-well plate in the ALI exposure chamber to evaluate the uniformity of particle deposition within the ALI. The measurements from fluorescein dosimetry and QCM revealed an uneven deposition between wells of the ALI exposure chamber. The performance of the QCM system was also evaluated using two different methods. First, using fluorescein deposition in one well, depositions in three other wells were estimated, which was then compared to the actual QCM readings placed inside the same wells. Second, using the QCM measured deposition in one well, the deposition in three other wells was estimated and compared to deposition measured by fluorescein dosimetry. For both methods, the comparison between the expected mass deposition and actual deposition yields a linear fit with the slope ~1. This good fit suggests that QCM systems can be used to measure real-time mass deposition in an electrostatic ALI system.