Figure 4From: Critical role of surface chemical modifications induced by length shortening on multi-walled carbon nanotubes-induced toxicity XPS analysis of S- and L-CNT. XPS spectra C1s core level for (a) S-CNT and (b) L-CNT and (c) corresponding quantitative analyses of the surface chemical composition extracted from the C1s, O1s and Fe2p spectra. Data in (c) are given as mean ± SEM.Back to article page