At the University of Twente in The Netherlands, scientists have come up with a rapid and inexpensive way of separating out DNA fragments from a sample. The technology will help speed up DNA sequencing, which normally relies on using computers to virtually combine millions of DNA fragments into a single string.
Currently, the so-called fractionation process can take up hours, but thanks to a new microchip this can now be done on the order of minutes. Additionally, the output is pure DNA fragments from which salts, which tend to pollute the sample, are also removed.
Presently, electrophoresis is often used to separate DNA, which involves applying electricity to drag molecules along. Larger molecules, being harder to pull, don’t travel as much as smaller, lighter molecules. The new technique is a 2D version of traditional electrophoresis, involving pulses of an electric field situated perpendicular to the main one.
Because the perpendicular field fluctuates, the path of a molecule’s travel looks snake-like and is terminated on the edge of the chip where there is an array of channels. The further the channel from the starting point, the lighter the molecules that enter it. The advantage is that now there are different channels that contain molecules of very similar size and that a single channel doesn’t have to be used to process the entirety of the sample.
The new chip is able to separate fragments of lengths from 500 base pair to 10,000 base pairs within only a couple minutes.
Study in journal Microsystems & Nanoengineering: Exploiting biased reptation for continuous flow preparative DNA fractionation in a versatile microfluidic platform…