Lesions on the peritoneal face of the diaphragm after intra-peritoneal injection of 2 forms of carbon nanotube differing in aspect ratio. The figure shows sections through the peritoneal aspect of the diaphragm of C57BL/6 mice 6 months after intra-peritoneal injection of 10 μg of two separate forms of multi-walled carbon nanotube (CNT). Sections are stained with Haematoxylin & Eosin (panels A and C) or Picro-sirius red stain which stains collagen bright red (panels B and D). Mu = Muscle of diaphragm; G = granuloma; small arrows = mesothelium; large arrows = carbon nanotubes. C and D show a large granuloma sitting atop the muscle layer, caused by the presence of CNT in the form of long fibres (open arrows). A and B show the contrasting response to CNT in the form of tightly bound dense spherical aggregates (open arrows) which produces minimal tissue reaction. All images are taken at ×100 magnification bar = 100 μm.
Donaldson et al. Particle and Fibre Toxicology 2010 7:5 doi:10.1186/1743-8977-7-5