FIGURE 5.

Nanoparticle-induced cell death is not apoptosis. A, 5 × 10⁶ RAW264.7 cells were seeded into 100-mm culture dishes and incubated with LPS (10 ng/ml), CB nanoparticles (30 μg/cm²), or both for 24 h. One group was exposed to staurosporine (1 μm) as a positive control for apoptosis. After the culture period, DNA was isolated. DNA concentration was measured, and equal concentrations were loaded and run on a SYBR Green gel. The gel was visualized with ultraviolet light, and samples were examined for laddering. B, 3 × 10⁶ RAW264.7 cells/well were seeded into culture plates. Cells were exposed to CB nanoparticles (30 μg/cm²), TiO₂ nanoparticles (30 μg/cm²), or staurosporine (1 μm) for 24 h. Proteins were isolated, and Western analysis for the apoptosis-associated caspases 3 and 9 was performed.