Protective effect of Concanamycin A. Panel a-i: typical μXRF maps of P and Fe of macrophages unexposed (upper line - Conca) or exposed (lower line - Conca + SWCNT) to 50 μg/ml SWCNT for 3 hours in presence of 10 nM Concanamycin A (the color scale is a temperature scale, ranging from blue for low concentrations in the element of interest to red for high concentrations); right: P (green) and Fe (red) correlation images. The size of a pixel is 0.25 μm2 (scale bar: 10 μm). Panel a-ii: X-ray fluorescence spectra integrated exclusively over the scanned cells. Positions of Kα fluorescence peaks of phosphorus (P), sulfur (S), chlorine (Cl), potassium (K) and iron (Fe) are indicated. The inset represents zoomed areas around the positions of the Kα fluorescence peak of iron together with fits of its contribution (dashed lines). Panel b: quantification of isolated iron nanoparticles in the nucleus and the cytoplasm of macrophages exposed to SWCNT for 3 hours in absence (open bars) or presence (grey bars) of 10 nM Concanamycin A. *: p < 0.001 between groups. Panel c: Western Blot images of Phospho-p53 (53 kDa) and γH2AX (17 kDa) expression in macrophages exposed for 3 hours to 50 μg/ml SWCNT, in presence (+) or absence (−) of 10 nM Concanamycin A. ß-Actin is given as internal standard. Panel d: quantification of Phospho-p53 and γH2AX expression in Western Blot, normalized to ß-Actin expression. *: p < 0.05 between groups. Conca: Concanamycin A.