FIGURE 5.

AgNP₁₅ induce cell death in human monocyte THP-1 cells. A and B, cell viability was assessed by flow cytometry using annexin-V-PI staining. C, caspase (Casp) processing was determined by Western blot, and caspase activity was quantified using a caspase assay, as described under “Experimental Procedures.” Cells were stimulated for 1 h (A and B) or 24 h (A–C) with buffer (Ctrl), 1–25 μg/ml AgNP₁₅ or 1 μm staurosporine (Stau). MW, molecular weight markers. D and E, quantifications of caspase-3 and caspase-4 activity. O.D., optical density. Data are means ± S.E. of three (A and B; D and E) or are from one representative experiment out of three (C). Differences were considered statistically significant as follows: *, p ≤ 0.05, **, p ≤ 0.01, and ***, p ≤ 0.005 versus control or appropriate diluent.