268971 Deposition of Non-Spherical Particles in a Bifurcating Airway
Title: Deposition of Non-Spherical Particles in a Bifurcating Airway
Poom Bunchatheeravate and Jennifer Curtis
Department of Chemical Engineering, University of Florida, Gainesville, FL 32611. USA
Particles between the sizes of 1-10um are more susceptible to deposition in the human lung. Previous investigations of particle deposition in the human airways focus on the deposition of spherical particles. Only a handful of studies focus on the effect of particle morphology. These studies include the deposition of fibrous particles in response to pollutants such as asbestos, deposition of porous particles for higher drug loadings, as well as deposition of nano-size particles. The current study seeks to quantify the deposition of different shaped particles and establish a relationship between particle shape and deposition. The airway model used in this study is that of a triple bifurcating airway that was glass blown with the dimensions similar to that of Weibel's Model A. The simplicity of the airway model helps to isolate the effect of particle morphology on deposition patterns. The particles used in this study were classified into three general shapes - spherical, rod-like, and flake-like. The effect of particle density was also studied for spherical particles and flake particles. All of the particles studied had a mean aerodynamic diameter between 1-10 microns. Particles were dyed using a near-infrared dye and sent into the airway model with a fixed volumetric flowrate. After the deposition, the particle were visualized using IVIS Lumina fluorescence imaging machine. The IVIS Lumina provides two essential pieces of information - the fluorescence image showing the position of particle and the photon counts emitted in each region of the airway model relating to the local concentration. The deposition in each individual airway was quantified for each type of particle. The deposition associated with each type of particle is compared and an empirical model was developed relating the deposition efficiency in each branching airway with the particle properties. It was found that the particle properties that influence the deposition are the particle Stokes number, the diffusion coefficient, the density and the sphericity.