Progress on several fronts is reported.

Progress has been made in the development of compact sensor arrays containing molecular electronic devices for detecting molecules of interest (especially biomolecules) with high sensitivity and selectivity. As described in somewhat more detail below, the sensory devices in these arrays are based on chemically functionalized semiconductor nanowires. Because of the small sizes of nanowire-based devices, these arrays could be extremely dense, enabling simultaneous detection of multiple molecular species of interest. In addition, in some cases, it should be possible to extend the limits of detectability to quantities as small as a single molecule.

A Basic Sensor Device of the type described in the text — one of many in an array — includes a semiconductor nanowire that serves as the channel of a field-effect transistor. When molecules of interest become bound to receptors on the nanowire, the electrical conductance of the nanowire changes.