Scanning electron micrograph of a cross section of the finished device. An array of densely spaced nanopillars constitutes the entropically unfavorable region. The pillar spacing was 135 nm and their width approximately 80 nm. Copyright © Cornell
Fluorescing DNA molecules show the separation of two different lengths of DNA. In the first image, DNA molecules pulled by a weak electric field gather at the edge of a sieve made of tiny pillars. After a stronger field pulse of two seconds, the shorter molecules were fully inserted, while the longer molecules remained partially in the open, entropically favorable region. When the field was removed, the longer molecules extracted themselves from the pillar region, as shown at right. Copyright © Cornell University
Cornell University researchers have demonstrated a novel method of separating DNA molecules by length. The technique might eventually be used to create chips or other microscopic devices to automate and speed up gene sequencing and DNA fingerprinting.
The method, which uses a previously discovered entropic recoil force, has better resolution -- that is, better ability to distinguish different lengths -- than others tried so far, the researchers say. They separated DNA strands of two different lengths, using their own nanofabricated device, and demonstrated that modifications would make it possible to separate strands of many different lengths.
A description of the experiment is scheduled to be published in the Oct. 1, 2002, issue of the journal Analytical Chemistry by graduate student Mario Cabodi, postdoctoral researcher Stephen Turner and Harold Craighead, the C.W. Lake Jr. Professor of Productivity.
Bill Steele | Cornell News
Biologists unravel another mystery of what makes DNA go 'loopy'
16.03.2018 | Emory Health Sciences
Scientists map the portal to the cell's nucleus
16.03.2018 | Rockefeller University
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...
The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...
At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.
When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...
At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.
Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...
16.03.2018 | Event News
13.03.2018 | Event News
08.03.2018 | Event News
16.03.2018 | Earth Sciences
16.03.2018 | Physics and Astronomy
16.03.2018 | Life Sciences