Liquid Transistor
Voltage controls fluid transport through nanochannels

Results: University of California, Berkeley, researchers have developed a nano-scale silicon device that acts like a transistor for fluids. By applying a voltage across the device, the researchers stopped and started the flow and controlled the concentration of ions and molecules moving through the device's 35-nanometer-high, one-micrometer-wide channels. In one experiment, the team, led by Arun Majumdar and Peidong Yang, increased the concentration of a dye solution twofold by applying a positive 50 volts across electrodes that intersected the channels.

Why It Matters: One potential application of nanotechnology is diagnostics and sensors that manipulate tiny volumes of liquid to detect and measure very low levels of specific molecules. Such "nanofluidics" need a component that controls the movement of liquids and molecules. The Berkeley device could serve that purpose.