Toxicity of Co
particles on BEAS-2B and NHBE primary cells. CellTiter-Glo assay (ATP measurement) (A). BEAS-2B cells were exposed to Co3O4 particles (0 – 1000 μg.mL−1 Co), latex beads LB-3 (0 – 1000 μg.mL−1) as a negative control, or soluble cobalt (CoCl2) for 72 h (0 – 50 μg.mL−1 Co). The cellular ATP content was then evaluated (RLU, Relative Light Unit). Results were obtained from a minimum of three independent experiments, each performed in quadruplicate. Clonogenic assay (proliferation) (B). Example of Co3O4 particle effects on colony formation of BEAS-2B cells (μg.mL−1 Co). Colony numbers were determined following a 24 h exposure to Co3O4 particles and LB-3 (0 – 1000 μg.mL−1 Co and LB-3, respectively) and ten days of culture (time period needed to form colonies). Results were obtained from three to six biological replicates. IC50 (μg.mL−1 Co and LB-3, respectively) values obtained after exposure of BEAS-2B and NHBE cells to Co3O4 particles and latex beads (C).