Simulation of Nanotube Deposition in the Human Respiratory Tract

Abstract

The study investigates the behavior of singlewalled carbon nanotubes (SWCNT) and multiwalled carbon nanotubes (MWCNT) in the human respiratory tract. Particle geometries were modeled by assuming different dynamic shape factors for nanotubes oriented parallel and nanotubes oriented perpendicular to the air stream. Based upon these assumptions, particle-specific aerodynamic diameters were computed. Mathematical approaches to particle geometry were implemented into a stochastic particle transport and deposition model which is founded on the Monte Carlo concept for the generation of high numbers of particle trajectories through the lung airways. Nanotube deposition was simulated for sitting breathing conditions and heavywork breathing conditions. According to the results obtained from the model, SWCNT are characterized by significantly higher total deposition than MWCNT. With increasing respiratory flow rate and aspect ratio, total deposition of both types of nanotubes is slightly reduced. MWCNT have the tendency to be deposited in more distal lung regions than SWCNT. Hygienic consequences of this deposition behavior are discussed.