TABLE 2.
Single-channel conductances in the presence of polymer nonelectrolytes applied from one side
| Nonelectrolyte | Rh (nm) | γin (pS) | γout (pS) | χ (mS/cm) |
|---|---|---|---|---|
| Control | — | 402.8 ± 5.1 | 400.0 ± 8.0 | 15.24 ± 0.03 |
| Ethylene glycol | 0.272 ± 0.002 | 305 ± 13 | — | 8.66 ± 0.02 |
| Glycerol | 0.311 ± 0.002 | 293 ± 13 | — | 8.68 ± 0.04 |
| PEG 200 | 0.445 ± 0.011 | 297 ± 13 | 257.7 ± 5.8 | 7.72 ± 0.02 |
| PEG 300 | 0.532 ± 0.002 | 301 ± 17 | 263.6 ± 7.7 | 7.70 ± 0.02 |
| PEG 400 | 0.617 ± 0.005 | 315 ± 11 | 276.5 ± 3.1 | 7.56 ± 0.03 |
| PEG 600 | 0.746 ± 0.003 | 345.6 ± 7.2 | 276 ± 11 | 7.52 ± 0.02 |
| PEG 1000 | 0.951 ± 0.010 | 369.2 ± 4.7 | 274.9 ± 8.6 | 7.51 ± 0.03 |
| PEG 1540 | 1.156 ± 0.013 | 389.4 ± 9.2 | 306 ± 19 | 7.42 ± 0.02 |
| PEG 2000 | 1.391 ± 0.006 | 391.6 ± 8.7 | 386.8 ± 8.8 | 7.44 ± 0.04 |
| PEG 3400 | 1.839 ± 0.020 | 399.0 ± 8.5 | 388.8 ± 2.9 | 7.46 ± 0.03 |
| PEG 4000 | 1.911 ± 0.005 | 395.3 ± 6.1 | 394.5 ± 6.4 | 7.38 ± 0.02 |
Rh is the hydrodynamic radius obtained from viscosity measurements; γin is the inward single-channel conductance in the presence of polymers applied from the intracellular side of membrane patches; γout is the outward conductance in the presence of polymers applied from the extracellular side of membrane patches; and χ is the solution conductivity in the absence (control) or presence of polymers. Mean single-channel amplitudes at different voltages (n = 5–20 from at least five different patches) were used to construct I–V relationships and calculate slope conductances and their standard errors. Each value for the bulk conductivity represents the mean ± SE of five observations.