Sorting by diffusion: An asymmetric obstacle course for continuous molecular separation

Chia Fu Chou, Olgica Bakajin, Stephen W.P. Turner, Thomas A.J. Duke, Shirley S. Chan, Edward C. Cox, Harold G. Craighead, Robert H. Austin

Research output: Contribution to journalArticlepeer-review

212 Scopus citations


A separation technique employing a microfabricated sieve has been demonstrated by observing the motion of DNA molecules of different size. The sieve consists of a two-dimensional lattice of obstacles whose asymmetric disposition rectifies the Brownian motion of molecules driven through the device, causing them to follow paths that depend on their diffusion coefficient. A nominal 6% resolution by length of DNA molecules in the size range 15-30 kbp may be achieved in a 4-inch (10-cm) silicon wafer. The advantage of this method is that samples can be loaded and sorted continuously, in contrast to the batch mode commonly used in gel electrophoresis.

Original languageEnglish (US)
Pages (from-to)13762-13765
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number24
StatePublished - Nov 23 1999

All Science Journal Classification (ASJC) codes

  • General


  • Brownian motion
  • DNA fractionation
  • Microfabricated array


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