Viability of A549 (a, b, e) and human connective tissue (c, d, f) cells after exposure to Selol-PVM/MA nanocapsules (SPN) (a, c), free Selol (S) (b, d), blank polymeric nanoparticles without Selol (Bl) (a, c) or sodium selenite (SS) (e, f) at 50, 100 and 150 μg/mL Se for 24 h, 48 h and 72 h. All of the values were normalized according to the control group at 24 h (100%). The time-dependent proliferation of control cells was significantly different. *Statistically significant compared with the control group at the corresponding treatment period (p < 0.05). Influence of SPN at a concentration of 100 μg Se/mL on the proliferation of A549 (g) and human connective tissue (h) cells evaluated after different treatment times. Pairs of means in a same graph identified with different letters are significantly different (p < 0.05).