Cytotoxicity assessment of bDLE and HIV-1 inhibition activity. A) HeLa-CD4-LTR-β-gal cells (5 × 104 cells/well) and B) HIV-1IIIB cell-free viruses (MOI 0.2-0.5) were challenged with two-fold serial dilutions of bDLE. Cell viability and β-gal activity were measured with a luciferase-based assay 24 h after nanosilver exposure. Percentage values are relative to the positive control (no compound treatment). The data represent the means ± standard deviations from three separate experiments, each of which was carried out in duplicate.