Long double-stranded DNA molecules were separated in microfabricated hexagonal arrays in less than 1 min, several orders of magnitude faster than by using conventional technology. DNA samples were first concentrated at the entrance to the array in a thin band by entropic focusing. They were then separated by pulsed field electrophoresis. T4 (168.9 kbp) and λ (48.5 kbp) DNAs could be resolved into two clearly separated bands in ∼10 s in these experiments. This corresponds to a mass resolution of 6% in 11 min in a 1-cm-long array.
