Figure 1

Cell viability of MCF-7 cell line and PBMC treated with colloidal silver. Cells (5 × 10³ cells/well) were plated on 96 flat-bottom well plates, and incubated 24 h at 37°C in 5% CO₂ atmosphere. After incubation, culture medium was removed, and colloidal silver diluted in the same medium was added at concentrations ranging from 1.75 to 17.5 ng/mL. The plates were then incubated for 5 h at 37°C, and 5% CO₂ atmosphere. Thereafter, the supernatant was removed and cells were washed twice with DMEM/F-12 medium. Cell viability was determined by the trypan blue exclusion method, and cytotoxicity was expressed as the concentration of 50% (LD₅₀) and 100% (LD₁₀₀) cell growth inhibition. The experiments were performed in triplicates; data shown represent mean + SD of three independent experiments. *P < 0.05 as compared with untreated cells.