Analysis of Ni-CNT bonds in the lung and lymph nods by STEM-EDX. Rats were instilled by 2 mg of MWCNT. STEM-EDX analysis was performed for Ni and MWCNT detection on ultrathin sections. Spectrum of Ni analysis by EDX probe was performed during 60s in absence (A) or in presence (B) of MWCNT agglomerates. To observe the localization of Ni and MWCNT agglomerates in organism, (C) TEM photo of macrophage contains MWCNT agglomerates and (D) superposition of Ni position obtained with EDX probe (Resolution: 256 × 200; Dowell time: 800 ms; Frames: 256) in the cells were performed and reveal that MWCNT is colocalized with Ni.