Principles of a nanoscale DNA scanner.

A nanofluidic device for the routine stretching of single DNA molecules was hypothesised and tested. The device consists of an entrance channel leading to a post-field preceding an elongational flow field. The device facilitates each molecule's coil-to-stretch transition, counteracts its entropic recoil, and presents a stream of moving stretched molecules for detailed single-molecule time-of-flight measurements. The physics of DNA stretching was explored in a device where there was a juxtaposition of hexagonal upright post arrays with lithographically defined elongational flow fields.