Fig. 5From: Comparative carcinogenicity study of a thick, straight-type and a thin, tangled-type multi-walled carbon nanotube administered by intra-tracheal instillation in the ratSEM image of MWCNT-A fibers engulfed by an alveolar macrophage. Arrows point to two fibers penetrating the macrophage cell membrane. The right panel shows a higher magnification of the boxed section. Straight, needle like MWCNT-A fibers are present in irregular bundles associated with the macrophageBack to article page