Fig. 2.

Schematics showing the cell exposure procedure for chronic and nonchronic samples. (A) Chronic cell samples were plated, and NPs/media (0.1 nM NPs) were added after 24 h. NP/media solutions were changed 3 d later, and cells were passaged after an additional 3 d to start a new cycle. (B) Nonchronic cell samples were plated and NPs/media (0.1 nM NPs) were added after 24 h. NP/media was changed to just media after another 24 h. Media was refreshed 2 d later, and another 3 d later, the cells were passaged. (C) After the first week, the nonchronic subsequent passage cycles followed the chronic sample schedule, with no NPs added. Controls followed same schedule, with no NPs ever added.