Figure 1
From: Pulmonary surfactant inhibition of nanoparticle uptake by alveolar epithelial cells
(a) Schematic of particles entering the lungs during respiration. Lung sections including trachea, bronchi, bronchioles and alveolar air sacs are depicted. Airway diameters decrease in the same order from 12 mm to 200 µm. Nanoparticles can diffuse deeply and enter the alveolar air sacs. (b) Alveolar epithelium is composed of type I and type II cells. Type II cells secrete surfactant to alveolar lumen which then forms surfactant monolayer at air–liquid interface, tubular myelin and lamellar body structures in the surfactant film. (c) Total lung, i.e. tracheobronchial plus alveolar, and alveolar deposition fractions reproduced from IDEAL model calculations in Ref.4. Shaded area marks the deposition fraction of nanoparticles, diameter in the range 10–100 nm, in the alveolar region equal to 15–32%.
