Table 2.
Dose data for all cell culture studies with silica particles (100 µg mL−1) in a 24-well plate (2 cm2, 640 µL, 48,000 cells).
| Silica (SiO2) concentration/mmol L−1 | Silica particle concentration/L−1 | Silica particle surface/m2 per particle | Total silica particle surface/m2 L−1 | Total silica particle surface per well (640 µL)/m2 | Total silica particle surface per cell (48,000 cells)/µm2 | Total silica concentration after complete sedimentation in the well/particles m−2 | |
|---|---|---|---|---|---|---|---|
| Nanospheres | 1.7 | 4.42 × 1014 | 1.13 × 10−14 | 5.0 | 3.2 × 10−3 | 67,000 | 1.41 × 1015 |
| Submicrospheres | 1.7 | 7.85 × 1012 | 1.66 × 10−13 | 1.3 | 8.3 × 10−4 | 17,000 | 2.51 × 1013 |
| Submicrorods | 1.7 | 2.77 × 1013 | 8.01 × 10−14 | 2.2 | 1.4 × 10−3 | 29,000 | 8.86 × 1013 |
| Microspheres | 1.7 | 1.20 × 1012 | 5.81 × 10−13 | 0.70 | 4.5 × 10−4 | 9,300 | 3.84 × 1012 |
| Microrods | 1.7 | 1.06 × 1013 | 1.96 × 10−13 | 2.1 | 1.3 × 10−3 | 28,000 | 3.40 × 1013 |
As the cytotoxic effects of particles have been related to their total surface area, also with respect to the number of cells, the data were converted to different ratios (see discussion).