title: Particle dynamics and deposition in true-scale pulmonary acinar models.
abstract: Particle transport phenomena in the deep alveolated airways of the lungs (i.e. pulmonary acinus) govern deposition outcomes following inhalation of hazardous or pharmaceutical aerosols. Yet, there is still a dearth of experimental tools for resolving acinar particle dynamics and validating numerical simulations. Here, we present a true-scale experimental model of acinar structures consisting of bifurcating alveolated ducts that capture breathing-like wall motion and ensuing respiratory acinar flows. We study experimentally captured trajectories of inhaled polydispersed smoke particles (0.2 to 1 μm in diameter), demonstrating how intrinsic particle motion, i.e. gravity and diffusion, is crucial in determining dispersion and deposition of aerosols through a streamline crossing mechanism, a phenomenon paramount during flow reversal and locally within alveolar cavities. A simple conceptual framework is constructed for predicting the fate of inhaled particles near an alveolus by identifying capture and escape zones and considering how streamline crossing may shift particles between them. In addition, we examine the effect of particle size on detailed deposition patterns of monodispersed microspheres between 0.1-2 μm. Our experiments underline local modifications in the deposition patterns due to gravity for particles ≥0.5 μm compared to smaller particles, and show good agreement with corresponding numerical simulations.
authors.affiliation: Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa.
authors.forename: Rami
authors.initials: R
authors.lastname: Fishler
authors.affiliation: Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa.
authors.forename: Philipp
authors.initials: P
authors.lastname: Hofemeier
authors.affiliation: Department of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Haifa.
authors.forename: Yael
authors.initials: Y
authors.lastname: Etzion
authors.affiliation: Department of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Haifa.
authors.forename: Yael
authors.initials: Y
authors.lastname: Dubowski
authors.affiliation: Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa.
authors.forename: Josué
authors.initials: J
authors.lastname: Sznitman
mesh_terms: D000336:Aerosols; D001239:Inhalation; D008954:Models, Biological; D010316:Particle Size; D052638:Particulate Matter / Q000378:metabolism; D011650:Pulmonary Alveoli / Q000502:physiology*
chemical_list: D000336:Aerosols; D052638:Particulate Matter