Fig. 8

The organ distribution study of carbon black (CB) nanoparticles as a reference material. The hydrodynamic size of CB was controlled by dispersing them with different amounts of serum (i.e., 0, 1, and 3% mouse serum). The suspensions of CB with different hydrodynamic sizes were injected at 500 µg/mouse to eight-week-old female ICR mice via the tail vein. Then, the concentration of CB in organs was measured at days 1 and 7 by the identical method described for the ND. (a) The dispersion of CB with 0, 1, and 3% mouse serum produced a different set of hydrodynamic sizes. (b) The smaller hydrodynamic size showed more homogeneous dispersion. (c) The standard curve fit of CB samples by absorbance at 750 nm wavelength. The organ distribution of CB at (d) 1 and (e) 7 days post-injection. The Pearson correlation test between the hydrodynamic size and the percentage of initial treatment dose (%ID) per organ at day 1 [(f) liver, (g) lung, and (h) spleen] and 7 [(i) liver, (j) lung, and (k) spleen]. The correlation patterns between the hydrodynamic size and concentration of particles in organs were similar to those of NDs. Data are expressed as mean ± SEM for each group (n = 3 per group for hydrodynamic size and polydispersity; n = 2 for the standard curve fit; n = 4 per group for organ distribution of CB)