Single Molecule Analysis of Electrodynamically Stretched DNA in Nanochannels

A rapid (~20 ms) and precise (~110 nm) analytical method is presented for stretching and interrogating single DNA molecules. DNA strands were driven electrophoretically from a nanoslit into a nanochannel to confine and dynamically elongate them for repeated detection via laser induced fluorescence. Photon bursts were modelled analytically and DNA conformation, length, speed, and fluorescence intensity were measured simultaneously. The confluence of these measurements is a step forward towards applications limited by analysis time and spatial resolution, such as single molecule genomic sequencing. Several aspects of the translocation of DNA through a nanochannel were investigated, including stretching and speed as a function of electric field, and speed as a function of folding and length.