Fig. 2.

Cell viability measured by MTS assay in HT-1080, A549, and CCD-34 Lu cells treated with increasing concentrations of Ludox® NPs SM30 in medium with 3 % of serum (a) or without serum, followed by a recovery for 3 or 22 h in complete medium (10 % of serum) (b). The data represent mean ± SD (3 ≤ n ≤ 15). *p < 0.05, **p < 0.01 (t test; treated vs. control cells)