Table 3. Effect of Sequential Dilution of a 500 μg/mL SWCNH-ox Stock Dispersion in RPMI +10% FBS Cell Culture Medium on Hydrodynamic Size and Charge Obtained from Both Dynamic Light Scattering and Tunable Resistive Pulse Sensing.
| dynamic light scattering (DLS) |
tunable resistive pulse sensing (TRPS) |
||||||
|---|---|---|---|---|---|---|---|
| SWCNH-ox (500 μg/mL) dilution in RPMI+10% FBS | expected SWCNH-ox concentration (μg/mL) | dh,z-ave (nm) | PdI | ζ (mV) | size mean (nm) | size mode (nm) | concentration (#/mL) |
| 1:10 | 50 | 311 ± 11 | 0.37 | –9.3 ± 1.0 | 317 | 228 | –a |
| 1:50 | 10 | 223 ± 1 | 0.28 | –7.3 ± 0.3 | 291 | 204 | –a |
| 1:100 | 5 | 240 ± 4 | 0.48 | –7.6 ± 1.0 | 315 | 210 | 3.2 × 10010 |
| 1:500 | 1 | 70 ± 2 | 1 | –7.6 ± 0.9 | 313 | 223 | 6.9 × 10009 |
| 1:1000 | 0.5 | 43 ± 2 | 1 | –8.0 ± 0.7 | 297 | 208 | 5.7 × 10008 |
a
Concentration was too high, resulting in pore clogging. The applied pressure had to be reduced to near 0 (0 for 1:10 and 0.5 Pa for 1:50), which results in unreliable measurements. Stock dilution was necessary.