DNA transport by a micromachined Brownian ratchet device

We have micromachined a silicon-chip device that transports DNA with a Brow nian ratchet that rectifies the Brownian motion of microscopic particles. T ransport properties for a DNA 50-mer agree with theoretical predictions, an d the DNA diffusion constant agrees with previous experiments. This type of micromachine could provide a generic pump or separation component for DNA or other charged species as part of a microscale lab-on-a-chip. A device wi th reduced feature size could produce a size-based separation of DNA molecu les, with applications including the detection of single-nucleotide polymor phisms.