Field-effect control of protein transport in a nanofluidic transistor circuit

Electrostatic interactions play an important role in nanofluidic channels when the channel size is comparable to the Debye screening length. Electrostatic fields have been used to control concentration and transport of ions in nanofluidic transistors. Here, we report a transistor-reservoir-transistor circuit that can be used to turn on or off protein transport using electrostatic fields with gate voltages of +/- 1 V. Our results suggest that global electrostatic interactions of the protein were dominant over other interactions in the nanofluidic transistor. The fabrication technique also demonstrates the feasibility of nanofluidic integrated circuits for the manipulation of biomolecules in picoliter volumes.