Figure 2.

Relative effectiveness of competing selenium forms for inducing in vitro cytotoxicity in malignant mesothelial cells. (A) CNPnSe induces higher cytotoxicity in MM at lower doses than selenite (Na₂SeO₃ ) or free selenium nanoparticles (nSeBSA). (B) Control experiments showing only minor effects of the BSA additive, either independently or synergistically, (C) Control experiments to test the independent or synergistic effects of the pure carbon nanoparticles and oxidized glutathione byproduct, GSSG. (D, E) Cellular internalization of CNPnSe. Thin section TEM. N: nucleus. C: cytoplasm. M: cell membrane. White arrows: Selenium-carbon nanocomposite particles within cytoplamic vacuoles. Cells were exposed to increasing μM doses of selenium composites for 72 hrs. Equivalent doses: Se (1 μM) ≡ GSH (4 μM) ≡ GSSG (2 μM) ≡ CNPs (1 μg/ml) ≡ BSA (0.8 μg/ml). Together these results show that the desirable high cytotoxicity of the Se/C composite is a unique bifunctional nanoparticle effect that cannot be explained by the independent contributions of its components.