Nanomaterials, as a class of small-scale (<100 nm) substances with unique mechanical, optical and electrical properties, are increasingly being used in a wide range of industries. Their unique properties present new challenges to understanding the toxicity of these materials to humans and the environment. Lung is the major target organ for airborne nanoparticles. In vitro and in vivo exposure studies often rely on the use of suspended nanoparticle preparations. However, nanoparticles suspended in culture medium or physiologic saline solution tend to form micrometersized aggregates. Increasing evidence indicates that the degree of dispersion of nanoparticles has a strong influence on their biological activities. In this study, we test a new method of nanoparticle dispersion using natural lung surfactant, Survanta, as a dispersing agent. Dose dependence studies of Survanta were performed on single-walled carbon nanotube (SWCNT) dispersion. Our results show that Survanta at a concentration of 150 microg/ml, which is comparable to that found in normal rodent lungs, was optimal in dispersing SWCNT (0.1 mg/ml), producing well dispersed preparations as analyzed by microscopic and light scattering methods. This dose of Survanta was found to be non-toxic and non-inflammatory in vivo and in vitro when used alone, and did not mask the bioactivity of SWCNT. We also found that the dispersed form of SWCNT was more effective in inducing cytotoxicity and lung fibrosis than the non-dispersed form, indicating the importance of nanoparticle dispersion on biological activities. Since Survanta is commercially available and its one step nanoparticle dispersion is simple and rapid, this method provides major advantages over existing methods of nanoparticle dispersion. Furthermore, our stability studies showed that Survanta-dispersed nanoparticles remain well dispersed for months and upon dilution with aqueous medium.
Airborne-particles; Biological-effects; Biological-factors; Cell-alteration; Cell-biology; Cell-morphology; Cellular-reactions; Cytology; Exposure-assessment; Exposure-levels; Exposure-methods; Inhalation-studies; Irritants; Laboratory-animals; Lung-cells; Lung-irritants; Microscopic-analysis; Particle-aerodynamics; Particulates; Pulmonary-function; Pulmonary-disorders; Pulmonary-system-disorders; Respiratory-irritants; Respiratory-hypersensitivity; Statistical-analysis; Nanotechnology
The Toxicologist. Society of Toxicology 48th Annual Meeting and ToxExpo, March 15-19, 2009, Baltimore, Maryland