Microdevices for analyzing deoxyribonucleic acid (DNA) are ubiquitous in biological analysis, and techniques for analyzing DNA in microchips pervade the analytical chemistry literature. Use of nanochannels to study polymer physics has also become common. Owing to DNA's huge biological importance, its chemical properties have been thoroughly studied, and the experimental tools available for chemical analysis of DNA are numerous. The ubiquity and convenience of DNA has also led to extensive study of its physical properties. DNA is therefore an excellent example of how microscale systems facilitate analysis, as well as a model system for examining the effect of nanostructured devices on molecular transport of linear polyelectrolytes. Because the chemistry for fluorescently labeling DNA is relatively inexpensive and available commercially, fluorescence microscopy of DNA is a widely used means for visualizing DNA. It is quite routine to fluorescently label and observe the gross morphology of a single DNA molecule with 1-µm resolution, and thus straightforward experiments can be brought to bear on questions of molecular configuration.

DNA (and other idealized linear polymers) behave physically somewhere in between small molecules (which behave like idealized points) and particles (which behave like rigid continuous solid phases). The behavior observed (and the models that describe this behavior) incorporates aspects of point and particle behavior, and these behaviors are different depending on the type of transport.