Electrophoretic stretching of DNA molecules using microscale T junctions

Controlled trapping and stretching of DNA molecules are critical for single molecule genomic and polymer physics studies. The authors present a microfabricated T junction which can trap and stretch single free DNA molecules using electrophoretic forces. The device does not require special end functionalization of the DNA. They show that two physical mechanisms of stretching can occur depending on the length of the DNA relative to the channel width in the junction region. Stable trapping and stretching of DNA molecules up to lengths of 485kbp are demonstrated.