Nanoscale control and manipulation of molecular transport in chemical analysis

The ability to understand and control molecular transport is critical to numerous chemical measurement strategies, especially as they apply to mass-limited samples in nanometer-scale structures. The characteristics of nanoscale structures and devices highlighted in the examples discussed in this article include enhanced mass transport, accessing novel physical behavior, large surface-to-volume ratio, diminished background signals, and the fact that molecular characteristics can dominate the behavior of the structure. The control of nanoscale transport is physically embodied in different structures and experiments. Those structures and experiments highlighted here are featured because of their centrality (nanochannels and nanopores), their connection to more familiar macroscale phenomena (nanoelectrodes), and/or their ability to introduce control (stimulus-responsive materials) or because they represent especially interesting possibilities (stochastic sensing structures).