Occupational health risks associated with the production and use of nanomaterials are at this time undefined. Therefore, a need to conduct studies examining the health of effects of nanoparticle exposure is of great importance. However, nanoparticles agglomerate and clump in solution, making it difficult to accurately deliver nano-sized particles in an in vivo or in vitro experimental procedure. Therefore, a dispersal method which does not alter the biological activity of the particles surface and is not toxic to the lungs was developed. Experiments were conducted to determine the best method to suspend nanosized particles. Ultrafine and fine carbon black and titanium dioxide were suspended in a variety of suspension medias including phosphate buffered saline (PBS), rat and mouse bronchoalveolar lavage fluid (BALF), and dipalmitoyl phosphatidylcholine (DPPC). To assess and compare how the various suspension medias dispersed the particles, images were taken using light microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results of this study show that PBS is not a satisfactory media to prepare particle suspensions of nanosized particles. However, BALF is an excellent vehicle in which to suspend ultrafine particles. The use of protein alone or DPPC alone, in concentrations found in BALF, did not result in satisfactory dispersions. However, the combinations of protein plus DPPC are a satisfactory, although slightly less effective, substitute for BALF.
The Toxicologist. Society of Toxicology 46th Annual Meeting and ToxExpo, March 25-29, 2007, Charlotte, North Carolina