Pulmonary Bioassay Studies with Nanoscale and Fine-Quartz Particles in Rats: Toxicity is Not Dependent upon Particle Size but on Surface Characteristics

Pulmonary toxicology studies in rats demonstrate that nano-particles are more toxic than fine-sized particles of similar chemistry. This study, however, provides evidence to contradict this theory. The aims of the study were (1) to compare the toxicity of synthetic 50 nm nanoquartz I particles versus (mined) Min-U-Sil quartz (~500 nm); the toxicity of synthetic 12 nm nanoquartz II particles versus (mined) Min-U-Sil (~500 nm) versus (synthetic) fine-quartz particles (300 nm); and (2) to evaluate the surface activities among the samples as they relate to toxicity. Well-characterized samples were tested for surface activity and hemolytic potential. In addition, groups of rats were instilled with either doses of 1 or 5 mg/kg of carbonyl iron (CI) or various a-quartz particle types in phosphate-buffered saline solution and subsequently assessed using bronchoalveolar lavage fluid bio-markers, cell proliferation, and histopathological evaluation o