Figure 1

Images of nanoparticles and lung tissue. 1-1: TEM images of engineered nanoparticles (A) SiO₂, (B) Fe₃O₄, and (C) SWCNTs. 1-2: Lung tissue from rats instilled with 2 (top) and 10 mg/kg (bottom) of a test material and euthanized 5 weeks after the single treatment. (A) Control group, (B) 2 mg/kg and (E) 10 mg/kg nano-SiO₂, and (C) 2 mg/kg and (F) 10 mg/kg nano-Fe₃O₄. Particles were scattered in alveoli, and granulomas contained black particles (peaky arrow). (D) 2 mg/kg and (G) 10 mg/kg SWCNTs. An aggregate of inflammation cells (lymphocytes) (rotund arrow) around an area surrounded by quartz particle-containing, brown pellets were scattered in lung tissue. Magnifications were × 156.