Salt Pumping by Voltage-Gated Nanochannels

Scientific Achievement

Control over the polarization of nanochannels, which enables directed transport of charged molecules.

Significance and Impact

Pumping salt from high concentration reservoirs can be achieved through nanochannels under electrochemical control. This finding may have important applications in the process of water desalination.

a-b. The transmembrane potential Vbias is oscillated, while the potential of the membrane is held fixed, Vgate = 0 V.

c. Fluxes of cations and anions as a function of time.

d. Electric current, JC – JA and net salt flux JC + JA as a function of time.

e. Time integrals of the fluxes.

 

 

Research Details

  • We solved the Poisson-Nernst-Planck-Navier-Stokes (PNP-NS) system of coupled equations for nanochannels of varying lengths and radii between two reservoirs with saline solution.
  • The ionic transport was determined for a variety of solutions and applied bias and gate voltages in order to find optimal conditions for salt transport.
  • Tagliazucchi, M., Szleifer, I. "Salt Pumping by Voltage-Gated Nanochannels" J. Phys. Chem. Lett. 18, 2015, 3534–3539. DOI: 10.1021/acs.jpclett.5b01315

Work performed at Northwestern University