Table 2.
Physical properties of the solid substrates
| Substrate | Roughness parameters (nma) |
Avg contact angle (°) ± SD | Avg electrophoretic mobility [μs−1/(V/cm)] ± SDb | ||
|---|---|---|---|---|---|
| Ra | Rrms | Rz | |||
| Alumina | |||||
| Nanosmooth | 4.9 | 6.3 | 27 | 83 ± 2 | −1.24 ± 0.22 |
| Porous (20 nm and 200 nm) | NAc | NA | NA | NA | −0.29 ± 0.09 |
| Silica | |||||
| Nanosmooth | 0.3 | 0.3 | 1.6 | 89 ± 2 | −0.04 ± 0.04 |
| Circular wells | 6.7 | 7.5 | 26.7 | 98 ± 8 | |
| Thin rectangular wells | 6.4 | 7.3 | 23.3 | 94 ± 7 | |
| Wide rectangular wells | 5.2 | 6.1 | 19.3 | 95 ± 7 | |
a
One nanometer is 10−9 m.
b
Electrophoretic mobility was measured in tryptic soy broth (pH 7.18).
c
NA, not applicable; roughness and contact angle could not be determined accurately for the porous surfaces.