TABLE 1.

Parameters of the synthetic nanopores

Pore	Small diameter	Large diameter	Cone angle	DK (m2/s) 100 mM	DCa (m2/s) 100 mM	DK (m2/s) 20 mM	DCa (m2/s) 20 mM
1	54 Å	1580 Å	0.73°	1.37 × 10−9	0.388 × 10−9	—	—
2	52 Å	3982 Å	1.88°	1.29 × 10−9	0.336 × 10−9	—	—
3	46 Å	1850 Å	0.86°	—	—	1.03 × 10−9	0.173 × 10−9
4	46 Å	2560 Å	1.20°	1.20 × 10−9	0.323 × 10−9	1.06 × 10−9	0.181 × 10−9

Geometric parameters and effective diffusion coefficients for the four nanopores we used. All the nanopores have the double-cone geometry shown in Fig. 1 and are 12 μm long. The “small diameter” is the diameter at the center of the pore and the “large diameter” is the diameter at the mouths of the pore. These diameters were estimated as previously described (23). “Cone angle” is the angle of the pore wall above the long pore axis. D_K and D_Ca are the effective diffusion coefficients needed to reproduce the data (when experimental data was available to determine them). The cation concentration (100 mM or 20 mM) is indicated for each column. For comparison, the infinite-dilution, bulk values are 1.96 × 10⁻⁹ and 0.79 × 10⁻⁹ m²/s for K⁺ and Ca²⁺, respectively.