Influence of airspace geometry and surfactant on the retention of man-made vitreous fibers (MMVF 10a).

Abstract

Inhaled and deposited man-made vitreous fibers (MMVF) 10a (low-fluorine preparation of Schuller 901 insulation glass) were studied by electron microscopy in hamster lungs, fixed by intravascular perfusion within 23 ± 2 min (SD) of the initial inhalation. We found fibers on the surfaces of conducting airways and alveoli. In the airways, 89% of the fibers were totally and 11% partially covered by lining-layer material. In the alveoli, 32% of the fibers were totally submersed; others touched the alveolar wall, stuck at one end, bridging the airspace. Studies in a surface balance showed that fibers were immersed into the aqueous subphase by approximately 50% at film surface tensions of 20-25 mJ/m 2 and were submersed (totally immersed; i.e., totally surrounded by fluid) at approximately 10 mJ/m 2 . Fibers were also found to be phagocytosed by macrophages. We found a substantial number of particle profiles within alveolar blood capillaries. Fiber length and alveolar geometry appear to be important limiting factors for the submersion of vitreous fibers into the lungs' surface lining layer.

Differential pattern of deposition of nanoparticles in the airways of exposed workers

“…In the exposed workers, the small fraction of UFP (10–50 nm) were retained in the epithelial lining fluid and recovered by EBC, while the largest fraction of UFP (50–100 nm) were rapidly translocated to inner compartments. It is known that after particle inhalation and their deposition on the lung epithelium, the retention of particles starts with their wetting by surfactant and the epithelial lining fluid and their subsequent displacement from the air into the aqueous phase regardless of particle shape, surface topography, and surface-free energy (Geiser et al 2003). Our results support the statement by Moller et al that the probability of long-term particle retention in the airways is inversely correlated to particle size as was shown in both of our study groups.…”

Interaction of metal oxide nanoparticles with lung surfactant protein A

“…ALF, particles with a diameter of 1-6 µm are wetted and sink into the aqueous phase [42], whereas this mechanism is independent of shape, surface topography and surface free energy [43][44][45][46]. This process becomes even more efficient with decreasing particle size and this is expected to occur with nanoparticles, too [47].…”

In VivoParticle Uptake by Airway Macrophages in Healthy Volunteers

“…As a result, information on the functional properties of phagocytic cells (in particular their ability and time course for taking up particles), and the effect of macrophage numbers on these parameters, is lacking, especially when it comes to examining these properties in a dynamic, human in vivo model. Experimental techniques such as electron microscopy for in situ studies have been used mainly in animal models to examine phagocytic properties of lung cells (4)(5)(6)(7)(8). These studies have provided valuable information on the properties of lung phagocytes, although they require the use of special isolation and fixation techniques that prevent the examination of events in "real time."…”