Fig. 1From: The pulmonary toxicity of carboxylated or aminated multi-walled carbon nanotubes in mice is determined by the prior purification methodLibrary of MWCNTs used in the present study. a Illustration showing derivation of carboxyl and amine functionalized MWCNTs after purification by heat or acid treatment. b TEM images of the NC7000 MWCNT samples. Magnification bars are indicatedBack to article page