AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
An in Vitro Model for Tracking Translocation of Industrially Relevant Engineered Nanomaterials across the Alveolar Epithelium: The Importance of Size, Surface Chemistry, and Particle Kinetics
JOEL COHEN, Ramon Molina, Joseph Brain, Philip Demokritou, Harvard University
Abstract Number: 84 Working Group: Health Related Aerosols
Abstract Relatively little is known about the intracellular fate and function of industrially relevant engineered nanomaterials (ENMs). These interactions are important when considering inhalation exposure and subsequent translocation of ENMs across the nano-thin epithelial lining layer of the lung. Limited studies suggest a correlation between particle size and cellular uptake, though with conflicting results. Discrepancies in the literature may be attributable to limitations of fluorescent tracer particle models currently used. Herein we present a novel method for tracking well-characterized industrially relevant metal oxide ENMs by neutron activation. Nano-sized ceria dioxide of various sizes and silica dioxide coated-ceria dioxide particles generated by flame spray pyrolysis were neutron activated, forming the isotope 141Ce. Non-irradiated ENMs were characterized for specific surface area by nitrogen adsorption (BET), surface chemistry by x-ray photoelectron spectroscopy (XPS), crystallinity by x-ray diffraction (XRD), and morphology by transmission electron microscopy (TEM). ENMs were dispersed in liquid suspension following a previously described protocol and characterized for agglomeration and zeta potential by dynamic light scattering (DLS). ENM dispersions were applied to a monolayer of A549 cells in a transwell in vitro system. ENM trafficking was evaluated following 4, 24, and 48 hours of exposure by gamma spectrometry. A mass balance of particles was determined for various intra- and extracellular compartments to determine the fraction of ENMs that translocated across the cellular monolayer. Our results demonstrate the influence of particle size and chemical composition on ENM delivery to cells, cellular uptake, and cellular trafficking, with implications for preferential translocation across the alveolar epithelium following inhalation exposure.