Effects of particle agglomeration on pulmonary toxicity.
Toxicologist 2009 Mar; 108(1):127
Nanoparticles tend to agglomerate into um-sized structures upon suspension in biologically compatible media such as phosphate-buffered saline (PBS), due to the high ionic strength and near neutral pH of the media. Dispersion of nanoparticles in chemical surfactants is effective but is problematic because of bio-incompatibility or alteration of the nanoparticle surface. The effectiveness of albumin, phospholipid, dilute alveolar lining fluid, and an "artificial dispersion fluid" containing a phospholipid/albumin/PBS mixture in suspending ultrafine carbon black, ultrafine titanium dioxide, and multi-walled carbon nanotubes has been evaluated with dilute alveolar lining fluid and the "artificial dispersion fluid" proven to significantly enhance dispersion. Evidence indicates that at the low concentration used dispersion fluid does not mask the activity of the nanoparticle surface. Improved dispersion significantly increases the inflammatory potential of ultrafine carbon black in an intratracheal instilled rat model. Evaluation of the pulmonary responses to poorly dispersed vs well dispersed preparations of single-walled carbon nanotules (SWCNT) in a pharyngeal aspiration mouse model indicates that granulomas form at deposition sites of agglomerates, while more dispersed SWCNT structures avoid phagocytosis by alveolar macrophages, rapidly cross the alveolar epithelial lining and enter the interstitium where a persistent fibrotic response is initiated. Inhalation studies with SWCNT indicate that pharyngeal aspiration of dispersed SWCNT more closely mimics inhalation a dry aerosol of SWCNT than aspiration of a poorly dispersed suspension.
Airborne-dusts; Airborne-particles; Aerosol-particles; Biological-effects; Biological-function; Biological-systems; Biological-transport; Cell-biology; Cell-damage; Cell-function; Cell-metabolism; Cellular-reactions; Exposure-assessment; Exposure-levels; Exposure-methods; Inhalation-studies; Laboratory-animals; Molecular-biology; Particle-aerodynamics; Particulate-dust; Particulates; Respiratory-hypersensitivity; Respiratory-irritants; Respiratory-system-disorders; Nanotechnology
The Toxicologist. Society of Toxicology 48th Annual Meeting and ToxExpo, March 15-19, 2009, Baltimore, Maryland