Transport and sensing in nanofluidic devices.

Ion transport and sensing in nanofluidic devices are receiving a great deal of attention because of their unique transport properties and potential analytical applications. Some aspects of microscale transport transfer directly to the nanoscale, but nanofluidic systems can be significantly influenced by phenomena such as double-layer overlap, surface charge, ion-current rectification, diffusion, and entropic forces, which are either insignificant or absent in larger microchannels. Micro- and nanofabrication techniques create features with a wide range of well-defined geometries and dimensions in synthetic and solid-state substrates. Moreover, these techniques permit coupling of multiple nano- and microscale elements, which can execute various functions. We discuss basic nanofluidic architectures, material transport properties through single and multiple nanochannels, and characterization of single particles by resistive-pulse sensing.