Electrical modulation of ion concentration in dual-gated nanochannels

Coupled Poisson-Nernst-Planck and Stokes simulations demonstrate the operating principles of using electrical biases in dual-gated nano-fluidic channels to create localized and tunable solution zones of either depleted or accumulated ions. Scaling studies reveal that such ion modulations overcome the limit of counter-ion screening and remain effective even for channel widths greatly exceeding the Debye screening length. The underlying mechanism is attributed to the transport-induced de-screening of gating potentials.